The lone surviving gunman in the Mumbai attacks has entered a surprise guilty plea. Pakistani citizen Mohammad Ajmal Kasab, 21, had been charged with 86 separate offences including murder and waging war against India over his role in the November atttacks, which killed 166 people over three days. He pleaded not guilty to all the charges in May but suddenly stood up and said: "I want to confess" during a routine interrogation of witnesses in a Mumbai court. Kasab then recounted his role in the terror plot in a three-hour confession, officials said. He now faces a possible death sentence. He is the only one of the ten gunmen captured alive during the co-ordinated attacks on targets including two luxury hotels, a Jewish centre and the train station, but is among 38 people to be charged over the attack. India says most of the accused are in Pakistan. Closed-circuit video footage caught during the siege of India's financial and entertainment capital showed Kasab carrying an AK-47 assault rifle in Mumbai's main train station. Kasab's guilty plea came as US Secretary of State Hillary Clinton met Indian Prime Minister Manmohah Singh for private talks that are widely expected to include Indo-Pakistani relations. India says Pakistani security agencies nurtured militant groups like Lashkar-e-Taiba which India blames for the Mumbai attacks. Islamabad denies state involvement, has detained some suspects and pledged to prosecute those responsible.