MIDDLE EAST - A US military surveillance drone has been shot down by Iranian forces while flying over the Strait of Hormuz. Iran's Islamic Revolution Guards Corps (IRGC) said the aircraft had violated Iranian airspace, and that the incident sent a "clear message to America". But the US military insisted the drone had been over international waters at the time, and condemned what it called an "unprovoked attack" by the IRGC. President Donald Trump tweeted: "Iran made a very big mistake!" The incident comes at a time of escalating tension between the two countries.