Sales of Geiger counters have gone through the roof in Germany in recent days, and people have been buying so many iodine pills that medical experts have warned of the health risks of taking them. It only makes sense, said the Federation of German Pharmacists, "if there is a radioactive cloud directly over Germany."

Judging by the near-panic with which Europe's largest nation is responding to the Fukushima incident, one might assume that a toxic cloud had already arrived. The whole world is anxiously watching the video footage showing plumes of smoke rising from the stricken plant, and questions are being asked in most countries about the safety of nuclear power.

But the reaction has been strikingly angst-ridden in Germany, which is over 5,500 miles away from Japan. The Japanese, one could be forgiven for thinking, are facing their plight with a lot more stoicism than the Germans. The fear is driven in part by the evident similarities between the two highly developed, industrial nations, both known for their technological prowess and rigorous safety standards. If it can happen in Japan, then it could certainly happen here, say Germans, who have a high level of respect for Japanese engineering.

German commentators have proclaimed the end of nuclear power as a global source of energy - even as China and India reaffirmed their commitment to invest heavily in new plants to satisfy their surging energy needs.

Questions persisted for decades about the ability of the Mark 1 to handle the immense pressures that would result if the reactor lost cooling power, and today that design is being put to the ultimate test in Japan. Five of the six reactors at the Fukushima Daiichi plant, which has been wracked since Friday's earthquake with explosions and radiation leaks, are Mark 1s.

"The problems we identified in 1975 were that, in doing the design of the containment, they did not take into account the dynamic loads that could be experienced with a loss of coolant," Bridenbaugh told ABC News in an interview. "The impact loads the containment would receive by this very rapid release of energy could tear the containment apart and create an uncontrolled release."

The situation on the ground at the Fukushima Daiichi plant is so fluid, and the details of what is unfolding are so murky, that it may be days or even weeks before anyone knows how the Mark 1 containment system performed in the face of a devastating combination of natural disasters.

But the ability of the containment to withstand the events that have cascaded from what nuclear experts call a "station blackout" - where the loss of power has crippled the reactor's cooling system - will be a crucial question as policy makers re-examine the safety issues that surround nuclear power, and specifically the continued use of what is now one of the oldest types of nuclear reactors still operating.

The most obvious way would be through tax bills, if Europe agrees to ride to the rescue and help Greece deal with its mounting public and foreign debts. It is not yet clear what leaders of eurozone nations have agreed to do, but one thing is certain: any assistance will come at a cost that will ultimately have to be borne by taxpayers in the nations that contribute.

European citizens, both those within and those outside the eurozone, would even have to contribute indirectly if the International Monetery Fund was to get involved, since it is funded by a charge - known as a "quota" - paid by member nations. But their contribution would have been reduced proportionally with contributions made by non-European countries. In other words, the financial burden would have been more widely shared.

So the reasons why people outside Europe should care are broadly the same as the reasons why the Greeks should care. Going forth, they too are facing slower wage growth, rising taxes and rising retirement ages as governments everywhere - in the eurozone, the UK, the US and Japan - start slashing their debts.

"The consequence of a political crisis would worsen the risks for our economy and lead to intervention," he said. Portugal is burdened with high levels of debt, and is struggling to avoid an international bail-out similar to those of Greece and the Republic of Ireland. The government of Prime Minister, Jose Socrates, unveiled the latest in a series of austerity measures last Friday.

The plans, which included cuts to health and welfare budgets, were meant to reassure investors and fellow European Union members that it can meet its debt obligations without the need for outside help. However, the austerity package has met with fierce opposition, and the prime minister has warned that if the measures fail to win support, his country may be forced into a bail-out.

The main opposition party has now decided to formally oppose the plans which could lead to political deadlock. This could bring down the current minority government forcing a general election. "I have been fighting to avoid this scenario for six months," Mr Socrates told Portuguese television.

Ratings agency Moody's has decided to downgrade Portugal's sovereign debt rating by two notches from A1 to A3. "The cost of market funding is likely to remain high until the deficit has been reduced to a sustainable level and the prospects for economic growth have improved," it said in a statement. The downgrade will make it more expensive for Portugal to raise money on the international money markets. Moody's has also given a negative outlook on the new rating, which means its rating could be downgraded further.

The AP news agency said government supporters later broke up the rally by punching and attacking the protesters. A Facebook group, The Syrian revolution against [President] Bashar al-Assad 2011, is said to have called the march. A similar appeal on Facebook last month failed to bring protesters to the streets, but critics blamed a heavy security presence for the failure of that campaign.

Tuesday's march started after noon prayers in the old town of Damascus and fanned out to neighbouring streets, the witness told the BBC. He said the security forces did not use force against the protesters, but detained six of them. He added that more people were expected to join demonstrations after the evening prayers. A video posted on YouTube appeared to show the protest, with hundreds of marchers chanting slogans calling for freedom and an end to the emergency laws.

Calls for protests in Syria surfaced on Facebook after Egyptian activists succeeded in overthrowing President Hosni Mubarak last month after weeks of street demonstrations. Syria - like Egypt - is ruled through emergency law and suffers from high poverty and unemployment. Critics say corruption and cronyism are rife in Syrian business and political circles.

President Bashar al-Assad - who came to power in 2000 after three decades of rule by his father Hafez - has moved slowly to open up the economy, but his administration does not tolerate any dissent. There are thousands of political prisoners in Syrian jails, and major opposition groups are banned. The government also blocks access to several internet sites and maintains strict control of the media.

About half of the existing cables running across the Pacific are damaged and "a lot of people are feeling a little bit of slowing down of Internet traffic going to the United States," said Bill Barney, chief executive of Hong Kong-based cable-network operator Pacnet. He declined to name the damaged cables operated by other companies, but said Pacnet's cable system connecting Japan to the US isn't damaged so far.

Most international Internet-data and voice phone calls are transmitted as pulses of light via the hundreds of undersea fiber-optic cables. The cables, which can cost hundreds of millions of dollars, are typically owned by consortia of telecom companies, who share costs and capacity. While the clusters of glass fibers are enclosed in protective material, they remain vulnerable to undersea earthquakes, fishing trawlers and ship anchors. There are also many choke points around the globe, where a number of cables converge.

While the extent of the damage to undersea cables is unclear and financial losses unknown, operators said they are undergoing an inspection and looking to expedite restoration. More than 5,000 people have been confirmed dead or missing because of the quake and ensuing tsunami, according to Kyodo News. Japanese Prime Minister Naoto Kan has called the earthquake and its aftermath the biggest crisis in Japan's post-war history.

According to a Kyodo News survey, local governments in the devastated areas are unable to contact up to 30,000 residents. The Fire and Disaster Management Agency said the number of buildings that were completely or partially destroyed stood at more than 70,000 as of 11 pm Monday. Efforts to address the unprecedented damage and to secure the lives of survivors were under way in various sectors. Prime Minister Naoto Kan said at a morning meeting of the government disaster headquarters that emergency workers have so far rescued 15,000 survivors.

About 550,000 people had evacuated by Monday to about 2,600 shelters in six prefectures, but water, food and fuel are in short supply in various locations where they have taken refuge, while the capacities of some shelters have reached their limits.

Moreover, the Japan Meteorological Agency said the quake-hit Tohoku region will be hit by snow or rain on Wednesday, calling on evacuees to take care amid the cold weather which is expected to continue until Friday. The weather agency also warned of continued aftershocks. On Monday, a total of five such quakes measuring up to lower 5 on the Japanese seismic intensity scale of 7 were felt in Ibaraki, Miyagi, Fukushima and Nagano prefectures.

Major automakers and department store chains suspended their operations. Among them, Toyota Motor Corp will halt production at all domestic plants through Wednesday, which will cut its production by 40,000 units. Isetan Mitsukoshi Holdings Ltd closed its seven department stores in Tokyo and the vicinity. Communication failures continued mainly in quake-hit Miyagi and Iwate prefectures, with 566,000 phone lines and 216,300 fiber-optic connections remaining out of service as of 5 pm Monday.

The blast tore through the unit 2 structure at the Fukushima Daiichi complex and a hole has been found in the container. Japanese cabinet secretary Yukio Edano has told a press conference there is also currently a fire in unit 4 reactor. Prime minister Naoto Kan said radiation has spread from the reactors and that anyone living less than 20km away from the facility should leave the area. He said that those within the 20 to 30km radius should stay inside as the risk of a nuclear leak is rising. Mr Edano said efforts are being made to cool down all of the reactors using water injection but that radiation levels could affect people's health.

Two previous explosions occurred in buildings housing unit 1 and 3 reactors following last Friday's massive earthquake and tsunami. The latest blast occurred after cooling water dropped repeatedly in unit 2, with the nuclear fuel rods partially exposed - risking an overheat of up to a temperature of 2,200 degrees Celsius. Damage to the hermetically-sealed reactor container dramatically increases the risk of serious radiation leaks.

The ex-deputy director of the International Atomic Energy Agency (IAEA) told Sky News that the Daiichi unit 2 reactor may still deteriorate even more. "I think the situation is still very, very grim - we are by far not over the worst," Olli Heinonen said. The troubles at the Daiichi plant compound the immense challenges faced by the Tokyo government as it struggles to send relief to hundreds of thousands of people along the country's north-east coast.

A top Japanese official said the fuel rods in all three of the most troubled nuclear reactors at Daiichi appeared to be melting. Of all these troubles, the drop in water levels - risking overheating and meltdown - at unit 2 still has officials the most worried. "Units 1 and 3 are at least somewhat stabilised for the time being," Ryohei Shiomi, of Japan's Nuclear and Industrial Safety Agency, said. "Unit 2 now requires all our effort and attention."

In the west, government forces have moved into the rebel-held town of Zuwara and are shelling Misrata city. But the focus has also moved east to Ajdabiya, the last town before the rebel base in Benghazi. It seems rebel fighters have been hiding inside the oil installation in Brega in the daytime, in the belief that the government does not want to shell the facility, says the BBC's Jon Leyne in Benghazi.

Opposition sources are also saying there are divisions within the government ranks, with some troops apparently reluctant to fire on civilians, our correspondent adds. UN envoy Abdul Ilah Khatib has met Libyan Foreign Minister Moussa Kusa in the capital, Tripoli.

In the meeting, Mr Khatib, a former Jordanian foreign minister, reiterated demands for an end to the violence and requested access for humanitarian groups, a UN spokesman said. Foreign ministers of the G8 industrialised nations are discussing the crisis in Paris - but the BBC correspondent there says it is already clear that there are divisions over whether any intervention would be effective.

More than 1,000 Saudi troops rolled over the causeway that links it to the island kingdom and the United Arab Emirates also said it would send 500 police at the request of Bahrain's rulers after weeks of protests against the government and royal family. Over 60 percent of Bahrainis are Shi'ites who complain of discrimination at the hands of the Sunni royal family. Calls for the overthrow of the monarchy have alarmed the Sunni minority, which fears that unrest could serve non-Arab Shi'ite power Iran.

Iran, which sits across the Gulf from Bahrain, sharply criticised the Saudi intervention. "The presence of foreign forces and interference in Bahrain's internal affairs is unacceptable and will further complicate the issue," Foreign Ministry spokesman Ramin Mehmanparast said at his weekly news conference in Tehran.

The United States has urged Saudi Arabia, the world's top oil exporter and a key US ally in the Gulf Arab region, to show restraint, though analysts said the escalation showed the limits of US influence when internal security was threatened. In a sign that security in Bahrain could deteriorate, the US State Department advised against all travel to the island due to a "breakdown in law and order."

The intervention by Gulf Arab troops is highly sensitive in a region where tensions soared after the 2003 US invasion of Iraq overthrew a Sunni dictator and ushered in a Shi'ite-dominated government. Accusations already abound of Iranian backing for Shi'ite activists in Bahrain - charges they deny.

The most serious damages were near Kealakekua Bay and Kailua-Kona on the Big Island. Haleiwa and Keehi Lagoon on Oahu, as well as areas of Maui and Molokai, also lost significant value. At least 25 boats sank at Keehi Lagoon, and an undetermined number of homes may have been destroyed along the Big Island's west coast beyond the two previously reported, including one that floated out to sea.

No one was killed or injured during the tsunami, which arrived in Hawaii early Friday morning as a result of a magnitude 9.0 earthquake in Japan. "It's in the millions in terms of property, but it's very small in terms of personal injury and deaths. Of course, we're very, very fortunate," said Governor Neil Abercrombie.

Additional losses may pile up because thousands of Japanese tourists have already canceled vacations to Hawaii since the tsunami, dealing a crushing blow to the state's tourism-dependent economy. "The economic consequences will be severe for us," Abercrombie said. "It's going to be terrible. It's going to be rough. It's something we have to come to grips with."

Japanese stocks were pressured by news of another explosion at the Fukushima Daiichi nuclear power plant, this time at its No. 4 reactor. This was shortly after radiation levels rose sharply as the No. 2 reactor suffered an explosion following damage to its suppression pool. Japan's prime minister Naoto Kan said there's a high risk of elevated levels of radiation from the crippled reactors, and urged people within 30 kilometers of the plant to stay indoors.

"What the world is watching right now is whether Tepco's Fukushima nuclear power plant is going to turn into Chernobyl," said Norihiro Fujito, senior investment strategist at Mitsubishi UFJ Morgan Stanley Securities. "Foreign investors are rushing to sell nuclear-power-plant-related stocks," said Masayoshi Yano, senior market analyst at Meiwa Securities. "There is no sense of calmness to examine the health of the Japanese economy as a whole." Exporters were lower due to production halts with Toyota Motor down 7.4% and Sony down 8.9%.

It was hard to predict how the crisis at the crippled nuclear power plants will end, and that was boosting demand for safe-haven assets, said Deutsche Securities strategist Makoto Yamashita. Also, "there is a risk that, even if the government tries to provide fiscal help (on post-quake reconstruction), production activities and sentiment (among firms and households) will deteriorate sharply," he added.

"There was a huge explosion" between 6:00 am (2100 GMT Monday) and 6:15 am at the number-two reactor of Fukushima No.1 nuclear power plant, a Tokyo Electric Power Co (TEPCO) spokesman said. The government also reported apparent damage to part of the container shielding the same reactor at Fukushima 250 kilometres (155 miles) northeast of Tokyo, although it was unclear whether this resulted from the blast.

Chief Cabinet Secretary Yukio Edano told reporters the suppression pool of the number-two nuclear reactor appeared to have been damaged. This is the bottom part of the container, which holds water used to cool it down and control air pressure inside. Earlier a cloud of radioactive dust billowed from the Fukushima Daiichi power plant after it suffered its second explosion in three days.

The Fukushima crisis now rates as a more serious accident than the partial meltdown at Three Mile Island in the US in 1979, and is second only to the 1986 Chernobyl disaster, according to the French nuclear safety authority. After insisting for three days that the situation was under control, Japan urgently appealed to US and UN nuclear experts for technical help on preventing white-hot fuel rods melting. The International Atomic Energy Agency (IAEA) said it was "unlikely" that the accident would turn into another Chernobyl, but failed to rule it out completely.

Around the world, Germany and Switzerland reacted by suspending plans for new reactors. Italy and Poland said they would rethink plans to invest in nuclear energy, and Friends of the Earth urged the British government to scrap its own plans for new reactors. Andy Atkins, the campaign group's executive director, said: "We can't keep heading down the nuclear route until the lessons from this crisis have been learnt."

Millions of people faced a fourth night without water, food or heating in near-freezing temperatures along the northeast coast devastated by Friday's disasters. Meanwhile, a third reactor at a nuclear power plant lost its cooling capacity and its fuel rods were fully exposed, raising fears of a meltdown. The stock market plunged over the likelihood of huge losses by Japanese industries including big names such as Toyota and Honda.

On the coastline of Miyagi prefecture, which took the full force of the tsunami, a Japanese police official said 1,000 bodies were found scattered across the coastline. Kyodo, the Japanese news agency, reported that 2,000 bodies washed up on two shorelines in Miyagi. In one town in a neighboring prefecture, the crematorium was unable to handle the large number of bodies being brought in for funerals.

"We have already begun cremations, but we can only handle 18 bodies a day. We are overwhelmed and are asking other cites to help us deal with bodies. We only have one crematorium in town," Katsuhiko Abe, an official in Soma, told The Associated Press. While the official death toll rose to nearly 1,900, the discovery of the washed-up bodies and other reports of deaths suggest the true number is much higher. In Miyagi, the police chief has said 10,000 people are estimated to have died in his province alone.

Friday's double tragedy has caused unimaginable deprivation for people of this industrialized country - Asia's richest - which hasn't seen such hardship since World War II. In many areas there is no running water, no power and four- to five-hour waits for gasoline. People are suppressing hunger with instant noodles or rice balls while dealing with the loss of loved ones and homes.

Dozens of people were injured on Sunday as protesters pushed back police and barricaded roads. Bahrain's opposition said the foreign troops amounted to an occupation. A Saudi official said about 1,000 Saudi Arabian troops arrived in Bahrain early on Monday. The troops are part of a Gulf Co-operation Council (GCC) deployment, a six-nation regional grouping which includes Bahrain, Saudi Arabia, Kuwait, Oman, Qatar, and the United Arab Emirates.

It is believed they are intended to guard key facilities such as oil and gas installations and financial institutions. Bahrain's Shia majority has long complained of discrimination at the hands of the Sunni ruling elite, but large-scale protests broke out last month after the presidents of Egypt and Tunisia were toppled in uprisings.

In a statement issued before the arrival of the GCC troops was confirmed, the Shia-led opposition said: "We consider the arrival of any soldier, or military vehicle, into Bahraini territory... an overt occupation of the kingdom of Bahrain and a conspiracy against the unarmed people of Bahrain."