MUMBAI (Reuters/AFP) - The lone surviving gunman from last years Mumbai attacks made a surprise guilty plea on Monday, admitting to a role in the three-day rampage that killed 166 and raised tensions between India and Pakistan. Pakistani citizen Mohammad Ajmal Kasab, 21, had been charged with 86 separate offences including murder and waging war against India for his role in the Nov 26-28 assault. Mohammed Ajmal Kasab, 21, told a special prison court - where he had originally pleaded not guilty in May - that he wanted to confess, taking the judge, the prosecution and his own defence lawyer by surprise. I plead guilty, he told the court in Mumbai, before narrating how the attacks were carried out, and giving details of his journey from Pakistan with nine other gunmen. Kasab and accomplice Abu Ismail opened fire with AK-47 assault rifles and threw hand grenades at commuters at the Chhatrapati Shivaji Terminus, killing 52 and injuring 109 in the bloodiest episode of the 60-hour reign of terror. Kasab, who also placed an eight-kilogram bomb in a taxi that took him to the station and later exploded near Mumbais airport, killing the driver and a passenger, was the only one of the 10 gunmen to survive. I was firing and Abu was hurling hand grenades, he told the court, according to the Press Trust of India news agency. I was in front of Abu who had taken such a position that no one could see him. I fired at a policeman after which there was no firing from the police side. Judge M.L. Tahaliyani asked why he had not pleaded guilty at the outset. According to the domestic Press Trust of India (PTI) news agency, Kasab replied: Initially, Pakistan had not accepted my nationality. Now that they have, I am confessing. He declined to say how he knew, denied he had been pressurised into changing his plea and urged the court to accept his statement, the report added. Prosecutor Ujjwal Nikam told reporters outside court that Kasab had realised the cat was out of the bag after 134 witnesses gave evidence against him since the trial began in April. DNA, fingerprint and closed-circuit television evidence was also produced in court. Nikam linked the confession to the forthcoming trial in Pakistan of five men accused of involvement in the attacks, including key Lashkar-e-Taiba (LT) operatives Zarar Shah and Zaki-ur-Rehman Lakhvi, the alleged mastermind. The court can impose the maximum sentence of death. The charge sheet against Kasab, the nine dead gunmen and 35 other LT activists sought in connection with the attacks, including Lakhvi, accused them of carrying out a heinous criminal conspiracy. This was with the express intention to destabilise India, wage war against the country, terrorise its citizens, create financial loss and issue a warning to other countries, it added. Two other men are also on trial, Indian nationals Fahim Ansari, 35, and Sabauddin Ahmed, 24, who are said to have provided the group with invaluable logistical support before the attacks. Our Monitoring Desk adds: Kasab alleged that an Indian taught him Hindi and he was making a confession because Pakistan had abandoned him, reports CNN-IBN TV channel. He admitted he was a Pakistani.