After calling on the British government to exercise restraint in handling London riots, Iran said it was advising its citizens there to be on high alert. British Prime Minister David Cameron deployed tens of thousands of police in London and other major metropolitan areas to control riots that began last weekend. Cameron during an emergency session of Parliament said the rioting wasn\'t about economic issues but about a culture of violence. With a massive security presence on the streets of London, Iranian officials asked British police and security forces to show restraint. That came as London rapped Tehran for curtailing press freedoms. The Iranian Foreign Ministry said it advised Iranian nationals in London to be alert. Iranian President Mahmoud Ahmadinejad, in a statement published by state-funded broadcaster Press TV, spoke in favor of the rioters in London. \"The true opposition in Britain is the people that are pushed to the ground and beaten on London streets and slain and yet no one hears their voice,\" he was quoted as saying. Iran, following controversial elections in 2009, was chided by the international community for a crackdown on opposition protesters taking part in the so-called Green Revolution.