Hundreds of US and Afghan troops searched yesterday for four Al-Qaeda militants who escaped from the main US military detention center in Afghanistan in what is a major embarrassment for American forces. A police officer and senior Afghan government official in Kabul had earlier said one of the escapees from Bagram Air Base had been recaptured but local Afghan authorities said this was not so.Bagram district chief Kabir Ahmad said a man arrested at a mosque northwest of the base yesterday was not one of the escapees but someone with a mental disorder who had been mistaken for one of the four. A manhunt involving hundreds of US and Afghan troops backed by helicopters was launched on Monday after what was the first ever escape from the heavily guarded center deep within Bagram, the largest US base in Afghanistan.