Teams of American special forces have been authorised to conduct spying missions intended to pave the way for a military strike on Iran in case President Obama orders one, US government sources have confirmed. The military units would penetrate Iranian territory to reconnoitre potential nuclear targets and make contact with friendly dissident groups, according to a secret directive written by General David Petraeus. The documents existence was disclosed for the first time yesterday. It authorises an expansion in the use of US special forces throughout the Middle East, US officials said. However, it is the possibility of American troops operating covertly inside Iran that has the greatest potential to destabilise regional security. General Petraeus, the most senior American commander in the Middle East and Central Asia, relied on special forces to ensure the success of the US troop surge in Iraq in 2007. His order to increase the use of Delta Force, Navy Seal and Army Ranger units for intelligence gathering and combat missions could jeopardise US relations with allies in the region while intensifying a long-running turf war between US military intelligence and the CIA. The seven-page document, seen by The New York Times, remained classified yesterday, though it was written in September. Since then US military specialists working with Yemeni armed forces have killed 6 out of 15 leaders of al-Qaeda in the Arabian Peninsula. The raids followed reports linking the group to the murder of 13 Americans at Fort Hood, Texas, and the attempted Christmas Day bombing of a Northwest Airlines jet. The number of US special operations teams in Afghanistan has also doubled since the Petraeus directive, senior officials have said. Such teams are now believed to account for more than half of all combat operations in the Afghan war zone. Sending special forces into Iran would be controversial but one of the missions of US Special Operations Command, headed by Admiral Eric Olson, is to conduct reconnaissance in any country deemed to pose a threat. A Pentagon spokesman acknowledged to The Times that individual commanders have authority to conduct intelligence operations as they see fit. General Petraeus is a member of the Pentagon high command whose tasks include drawing up plans to destroy Irans nuclear infrastructure. Such plans are always going to be under serious consideration, Anthony Cordesman, of the Centre for Strategic and International Studies, said, because you are dealing with a serious threat. (The Times)