The warning from the Centre for the Protection of National Infrastructure [CPNI], which operates as part of the Security Service, comes as experts warned the deadly E.coli outbreak in Germany has highlighted the vulnerability of the food chain and how quickly bacteria can spread. The highly virulent strain has claimed 18 lives and left more than 1,800 seriously ill, with the true number of cases expected to be far higher.

A senior German doctor last night called for an investigation into the possibility that the bacteria had been spread deliberately.

Klaus-Dieter Zastrow, chief doctor for hygiene at Berlin's Vivantes hospital, said: "It's quite possible that there's a crazy person out there who thinks 'I'll kill a few people or give 10,000 people diarrhoea'. It's a negligent mistake not to investigate in that direction."

The CPNI has asked food and drinks producers, suppliers and supermarkets to tighten security at plants and depots and to identify vulnerabilities in supply chains. One official from the CPNI spoke about the threat at a meeting of food safety experts. Addressing a conference of the Society for General Microbiology, he said: "The UK suffers from a low level of malicious contamination of food by the bad, the mad and the sad. Now it has to consider the possibility of food supplies being disrupted by politically motivated groups."

US experts have warned that the dairy industry is particularly vulnerable, as adding just a few grams of botulinum toxin or ricin to a tanker load of milk could poison or even kill thousands of consumers. The report warns that it is harder to guarantee the security of produce grown abroad and imported to Britain.

The clashes, marking the anniversary of the Arab defeat in the 1967 Mideast war, drew Israeli accusations that Syria was orchestrating the violence to shift attention away from a bloody crackdown on opposition protests at home. The marchers, who had organized on Facebook, passed by Syrian and UN outposts on their way to the front lines.

"The Syrian government is trying to created a provocation," said Israel's chief military spokesman, Brigadier General Yoav Mordechai. "This border has been quiet for decades, but only now with all the unrest in Syrian towns is there an attempt to draw attention to the border." Human rights groups say President Bashar Assad's forces killed at least 25 people in northern Syria over the weekend, and another 65 activists were killed in the central city of Hama on Friday, as anti-government protests spread through the country demanding his resignation.

There was no Syrian comment on why the protesters were allowed to storm the border, apparently undisturbed by authorities.

While Libyan leader Muammar Gaddafi is trying to quash a rebellion in a country that holds Africa's largest crude reserves, Qatar, Kuwait and the United Arab Emirates are backing the insurgents.

The conflict underlines the difficulties the 50-year-old organization that accounts for about 40 percent of the world's oil may have in deciding production levels. Oil has gained 9.5 percent this year to trade at about $100 a barrel amid signs that the pace of the global economic recovery may be slowing. The Organization of Petroleum Exporting Countries will probably leave its output target unchanged on June 8, according to a Bloomberg survey of 30 analysts conducted May 24-31.

"Amid issues surrounding representation of Libya and oil prices correcting towards $100 a barrel, OPEC is likely to sit on the fence, deferring a decision on quotas for later," Harry Tchilinguirian, the head of commodity-markets strategy at BNP Paribas SA in London, said in an interview on June 1. "This does not mean individual countries may not take discretionary steps to increase output. OPEC has yet to fill the gap in the market left by Libya."

Gaddafi and his Libyan opponents may dispatch rival envoys to this week's meeting. Iran, which holds OPEC's rotating presidency, is sending the former head of its Physical Education Organization to lead the negotiations after President Mahmoud Ahmadinejad fired his oil minister on May 14. OPEC will need to boost output to 29.9 million barrels a day to meet average demand this year because of "roaring" growth in China, the group said in its most recent monthly report. That's 1 million barrels a day more than last month, according to data compiled by Bloomberg. The International Energy Agency said on May 19 that it saw "an urgent need" for more oil to help bring down high prices threatening economies.

Spain's 17 autonomous regions and its more than 8,000 municipalities, with 150 billion euros ($220 billion) of accumulated debt between them, have become the latest worry for investors in Spain and its sovereign bonds. Although the amount is less than a quarter of total public sector debt, regional debt has doubled since 2008. The 17 regions collectively exceeded official budget deficit limits in 2010, and appear likely to do so again this year despite repeated demands for compliance from the central government.

CATALONIA, AN ECONOMY THE SIZE OF PORTUGAL, says its deficit will be double the target. Vicente Tirado, a senior PP politician in Castilla-La Mancha, said the region was "totally bankrupt"; owed suppliers such as pharmaceutical companies that provide drugs for hospitals a total of 2 billion euros in unpaid bills; and would have trouble finding the money to pay the region's 76,000 civil servants next month. Marcial Marin, the PP's economy co-ordinator in the region, accused the departing Socialist government of "the height of irresponsibility" and alleged that unpaid bills were being destroyed to hide the evidence.

Results showed the PSD won 105 seats, or 39 percent of the vote, while the rightist CDS party obtained 24, allowing the two traditional government allies to have a strong majority in the 230-seat parliament. The Socialists won 73 seats, 24 less than in the last election. "I will direct all my efforts as rapidly as possible to guarantee the country and the Portuguese will have a majority government led by the PSD that will give stability for the next four years," Passos Coelho told his party after the election.

CDS leader Paulo Portas said he was ready to rule together with the Social Democrats, allowing the incoming government to implement the austerity measures agreed with the European Union and the IMF as part of the rescue package. "The country has shown unequivocal will to open a window of confidence and hope for the future," said Passos Coelho. The election result showed that many Portuguese blamed the Socialists, in power for six years, for the country's economic crisis.

Portugal faces its highest level of unemployment in three decades and the economy is expected to contract two percent both this year and next, presenting the new government with tough challenges as disposable incomes fall and austerity takes its toll. So far there have been few strikes or protests against austerity measures in Portugal, unlike Greece and neighbouring Spain, but analysts say that could change as the recession deepens.

Unease is growing within Papandreou's ranks about the consequences of waves of budget cuts demanded under successive deals with the European Union and IMF - and this could turn into alarm after at least 80,000 Greeks crammed a central Athens square to vent their anger over the nation's dire state.

As the government struggles to prevent Greece from defaulting on its debt, the Socialist cabinet will discuss informally on Monday the medium-term economic plan which will impose 6.4 billion euros (5.7 billion pounds) of extra austerity this year alone. This is just the first stage of a drive to turn the plan, agreed on Friday with the EU and IMF as the price of a new financial rescue, into law.

Papandreou will then present the plan to the political council of his PASOK party on Tuesday, before the cabinet clears it the following day and sends it to parliament. Greece's international lenders have made clear that the new bailout package, which would replace a 110 billion euro deal agreed only a year ago, depends on Athens keeping to its promises for further austerity and accelerated privatisations.

But the government is under huge pressure, not from the hooded radicals who battled police in the early days of the austerity drive, but from ordinary Greeks who are suffering badly under pay and pension cuts and soaring unemployment. On Sunday night people from Athens and far beyond the capital crammed into the city's Syntagma Square to show they are close to the limit of their endurance.

Until October, the Chinese were generally making up for their decreasing holdings in Treasury bills by increasing their holdings of longer-term US Treasury securities. Thus, until October, China's overall holdings of US debt continued to increase. Since October, however, China has also started to divest from longer-term US Treasury securities. Thus, as reported by the Treasury Department, China's ownership of the US national debt has decreased in each of the last five months on record, including November, December, January, February and March.

Prior to the fall of 2008, acccording to Treasury Department data, Chinese ownership of short-term Treasury bills was modest, standing at only $19.8 billion in August of that year. But when President George W Bush signed legislation to authorize a $700-billion bailout of the US financial industry in October 2008 and President Barack Obama signed a $787-billion economic stimulus law in February 2009, Chinese ownership of short-term US Treasury bills skyrocketed.

By December 2008, China owned $165.2 billion in US Treasury bills, according to the Treasury Department. By March 2009, Chinese Treasury bill holdings were at $191.1 billion. By May 2009, Chinese holdings of Treasury bills were peaking at $210.4 billion. However, China's overall appetite for US debt increased over a longer span than did its appetite for short-term US Treasury bills. In August 2008, before the bank bailout and the stimulus law, overall Chinese holdings of US debt stood at $573.7 billion. That number continued to escalate past May 2009 - when China started to reduce its holdings in short-term Treasury bills - and ultimately peaked at $1.1753 trillion last October.

As of March 2011, overall Chinese holdings of US debt had decreased to $1.1449 trillion.

Regrettably, it was also a day of historical failure: Instead of celebrating on Temple Mount, the paratroopers ran to the Western Wall. They simply got confused. That generation was still closely attached to the memory of the Diaspora, where the Kotel served as a symbolic substitute for Temple Mount. This period kept on extending and with the passage of time we saw emotional confusion between the substitute and the original.

Mordechai Gur indeed announced that "Temple Mount is in our hands," yet the focal point of the national and paratroop festivities was shifted to the Western Wall plaza. People forgot that while the Kotel is the closest thing to the real thing, it is not the thing itself. Our ancient forefathers clung to the Western Wall in the past for lack of any other choice.

However, we now have a choice. The Romans are gone, the Turks left, the Brits were expelled and the Jordanians were defeated. There is no longer any genuine obstacle preventing us from connecting to the site of our Temple. All we have is a rabbinical obstacle. The Chief Rabbinate feared that the holy mount will turn into a mass vacation spot and immediately after the war banned entry to Temple Mount. The logic behind the ban was the same logic that in the past prompted haredi rabbis in the Diaspora to object to Zionism - grave concern that secular pioneers would desecrate the sanctity of the land.

For 44 years now, police officers have been deployed at the entrance to Temple Mount; their mission is not only to prevent the construction of the Temple, but even mere Jewish prayer. Only Muslims are allowed to express their religious feelings there.

If you are a kippah-wearing Jew, the police officers will put you through a lengthy act of humiliation at the entrance to the Mount. Later they will keep a close eye on you to ensure you don't mutter some Psalms. On the occasion of Jerusalem Day let's all pray, outside the Mount for the time being, that this discrimination will end by the next Jerusalem Day.

It happened on Wednesday, Jerusalem Reunification Day, when hundreds of visitors - all of whom immersed in a mikveh (ritual bath) prior to coming and took other precautions required by Jewish Law - were allowed to enter the Temple Mount in groups of 30-40. Among them were several Cohanim (descendants of Aharon the Priest).

They spread their hands in the customary manner and recited, "May G-d bless and watch over your… May G-d shine His countenance upon and show you grace… May G-d raise His countenance towards you and grant you peace" (Numbers 6, from the portion to be read aloud this week in synagogues throughout the Jewish world).

Rabbi Yisrael Ariel, head of the Temple Institute and one of the paratroopers who helped liberate the Temple Mount in 1967, and who was miraculously saved from death at the time, recited aloud the blessing, "Barukh - Thou art the source of blessing, G-d, Who performed a miracle for me in this place." Many visitors and listeners, including policemen, recited "Amen!"

That wheat is now being harvested, and it seems the danger has been averted. This week China's agriculture minister Han Changfu predicted a bumper harvest, saying that a long-term increase in the production base as well as irrigation efforts aided wheat output. But even as Han stood in Henan wheat field celebrating a problem successfully averted, other worries were emerging. Parts of central China, including the middle and lower reaches of the Yangtze River, are experiencing the lowest levels of rainfall in 50 years.

The parched areas also happen to include much of China's main rice producing regions, which are in the early stages of their growing season. So for the second time in a year, a major grain crop in China is now at risk due to a shortage of water. So far no warnings of the seriousness of the FAO's February declaration on winter wheat have been issued. But anecdotal reports indicate some worries. A story by the state-run Xinhua news service late last month said that rice farmers in Hunan and Hubei provinces, two major rice growing areas, anticipated lower yields because of the drought. At the same time, the acreage of planted rice may climb thanks to higher prices, the Ministry of Agriculture said recently. That may help avoid too sharp a drop in overall output.

Prices of some agricultural products heavily dependent on abundant water supplies have shot up recently, particularly cabbage, celery and bok choy, but the state press has emphasized that grain prices shouldn't jump due to the drought. Although China has grown to an economic colossus in recent decades, its deadly famines of the 20th century aren't forgotten.

"There are number of ways that this plays out," says Zeigler. "Assuming a significant drop in production, China could opt to only draw down part of its reserves and seek to make up the rest on world markets. The world rice market is very thin, and that could quickly rattle the market just given size of China."

"Perhaps many towns and cities have simply been a little lucky up until this year," Alex Sosnowski, senior meteorologist for Accuweather.com, told FoxNews.com. "This is a sign of what we may see on a more frequent, periodic basis as the weather pattern cycles through, as it has over years."

Some of the towns and cities that have been hit this year include Philadelphia; Minneapolis; Dallas; Oklahoma City, Oklahoma; Little Rock, Arkansas; Tuscaloosa, Alabama; Raleigh/Sanford, North Carolina; St. Louis, Missouri; Bristol, Viriginia; and Reading, Kansas. Most recently, an exceptionally unusual tornado struck Springfield, Massachusetts, killing at least three people.

The increase in deadly tornadoes is due to a number of factors. First of all, as the population grows and expands into more rural and suburban area, tornadoes cause more destruction in areas that once would have seen far less damage. The La Nina weather phenomenon has also been said to contribute to the recent rise in tornadoes in the US. La Nina, an ocean-atmospheric event that can cause anomalies in weather patterns, can contribute to stronger jet streams over Northern America.

The strength of the jet stream is a key factor in severe thunderstorms and tornado formation. "The stronger the jet stream, the more air is pulled up from the surface," Accuweather.com severe weather expert Henry Margusity said. "The jet stream acts as a vacuum cleaner by pulling air up from the surface." Another factor is the movement of these jet streams. This year, jet streams have moved farther east than where they are typically located. This causes severe thunderstorms and tornadoes in these densely populated areas.

The ruling was in response to a lawsuit filed by Christa and Danny Schultz. Their son is among those scheduled to participate in Saturday's graduation ceremony. The judge declared that the Schultz family and their son would "suffer irreparable harm" if anyone prayed at the ceremony.

Texas Attorney General Greg Abbott said the school district is in the process of appealing the ruling, and his office has agreed to file a brief in their support.

"Part of this goes to the very heart of the unraveling of moral values in this country," Texas Attorney General Greg Abbott told Fox News Radio, saying the judge wanted to turn school administrators into "speech police. I've never seen such a restriction on speech issued by a court or the government," Abbott told Fox News Radio. "It seems like a trampling of the First Amendment rather than protecting the First Amendment."

Judge Biery's ruling banned students and other speakers from using religious language in their speeches. Among the banned words or phrases are: "join in prayer," "bow their heads," "amen," and "prayer." He also ordered the school district to remove the terms "invocation" and "benediction" from the graduation program. "These terms shall be replaced with 'opening remarks' and 'closing remarks,'" the judge's order stated. His ruling also prohibits anyone from saying, "in [a deity's name] we pray."

The Texas attorney general called the ruling unconstitutional and a blatant attack from those who do not believe in God - "attempts by atheists and agnostics to use courts to eliminate from the public landscape any and all references to God whatsoever. This is the challenge we are dealing with here," he said. "(It's) an ongoing attempt to purge God from the public setting while at the same time demanding from the courts an increased yielding to all things atheist and agnostic."

The judge did grant students permission to make the sign of the cross, wear religious garb or kneel to face Mecca. But that's not good enough for some students at the high school. "It's just a big surprise that one kid can come in and change what's been a tradition since Medina Valley started," student Abigail Russell told KABB-TV.

But the Reverend Barry Lynn, executive director of Americans United for Separation of Church and State, hailed the judge's decision. "This is a high school graduation," he told Fox News Radio. "It is not a church service." Lynn was critical of the attorney general's allegation that the ruling was an attempt to purge Christianity from the public square. "Any attorney general worth his salt would know that's the issue and that this is not about promoting atheism," he said. "That's ludicrous."

The brief recovery in prices in 2009, spurred by government aid to first-time buyers, has now been entirely snuffed out, and the average American home now costs 33 per cent less than it did at the peak of the housing bubble in 2007. The peak-to-trough fall in house prices in the 1930s Depression was 31 per cent - and prices took 19 years to recover after that downturn.

The latest Case-Shiller house price index was just one of a slew of disappointing economic data from the US yesterday, which suggested ebbing confidence in the recovery of the world's largest economy. The Chicago PMI manufacturing index showed a sharp slowdown in the pace of expansion in May, missing Wall Street forecasts and sending the index to its lowest since November 2009.

Economists warned not to expect any immediate relief to the gloom from the housing market. Banks continue to demand high deposits from potential buyers and are pressing on with foreclosures against those who have fallen behind on mortgages, adding to the glut of unsold homes on the market. Prices are back to their 2002 levels, according to the Case-Shiller National House Price Index out yesterday.

Witnesses also reported a strong smell of ash and sulphur. A dozen small earthquakes were recorded before the eruption began. The officials have issued a red alert - the maximum warning level for the area. Evacuation orders were issued for some 3,500 people, the local authorities said.

So far there have been no reports of any injuries. However, ash clouds have drifted to neighbouring Argentina where officials have ordered residents to stay indoors. A regional airport in the Argentine city of Bariloche has been closed due to the volcanic ash. Eyewitness Juli Kessler told the BBC she saw "big black clouds hanging over the Andes" and ash dust lying on the road.

It is the first time since 1960 that the volcanic chain has erupted. Chile is one of the most volcanic countries in the world.

"It was a C-minus week for the economy," said David Sowerby, a Bloomfield Hills, Michigan-based money manager at Loomis Sayles & Co, which oversees more than $150 billion. "These are the kind of weeks that remind investors stocks don't just go straight up. There was enough data this week to begin to connect the dots that uncertainty remains." Labor Department figures showed payrolls increased by 54,000 last month, falling short of the median forecast in a Bloomberg News survey that called for a rise of 165,000. The jobless rate climbed to 9.1 percent.

The biggest decline in the S&P 500 since August is creating a buying opportunity for investors, according to Blackstone Group LP's Byron Wien. The price-to-earnings ratio for the S&P 500 has fallen close to its lowest level in 2011, according to Bloomberg data. The index currently trades at 14.8 times earnings, near this year's low of 14.7 when it fell in March after Japan's earthquake.

"Investors should be looking for buying opportunities," said Wien, the vice chairman of Blackstone Advisory Partners, whose parent, New York-based Blackstone Group LP, is the world's largest private-equity firm. "The economy is not as bad as it looks right now. Corporate profits will be good, very good. People are asking me, 'Do you still think the market can get to 1,500 by the end of the year?' I do."