The lone surviving gunman in the Mumbai attacks pleaded guilty yesterday and gave a detailed account of the plot and his role in the rampage that left 166 people dead and paralysed the city for three days.

The confession was a big boost to India's claims that terrorist groups in Pakistan were behind the attack, and that Islamabad was not doing enough to clamp down on them. Pakistan has acknowledged the Mumbai attacks were partly plotted on its soil, severely straining relations between the nuclear-armed archrivals.

In a verbal statement, Ajmal Kasab described his group's journey from Karachi, Pakistan, on a boat, their subsequent landing in Mumbai on November 26, 2008, and his assault on a railway station and a hospital with a comrade he identified as Abu Ismail.

The other gunmen, also armed with automatic rifles and grenades, attacked a Jewish centre and two five-star hotels, including the Taj Mahal. The rampage ended at the historic hotel days later after commandos killed the attackers holed up there.

Earlier Kasab, 21, stood up before the special court hearing his case just as a prosecution witness was to take the stand and addressed the judge.

"Sir, I plead guilty to my crime," he said, triggering a collective gasp in the courtroom.

The statement was recorded and signed by Kasab, formally reversing his plea from innocent to guilty in the trial that started April 17.

Kasab told the court he worked as a shop assistant in Jhelum town in Pakistan. Unhappy with the low wages, he and a colleague named Muzzafar went to Rawalpindi city with the intention of becoming professional robbers, he said.