MUMBAI: An Indian judge on Thursday ruled that the trial of the sole surviving gunman of the Mumbai attacks would continue, despite the accused's confession to his role in the carnage.

Judge M.L. Tahaliyani described Mohammed Ajmal Kasab's confession as only a "partial admission" of guilt to the scores of charges the Pakistani national faces over the attacks, in which 10 gunmen killed 166 people in November.

"The statement made by accused number one (Kasab) is a partial admission," Tahaliyani said. "He has however not admitted to all of the 86 charges framed against him."

The prosecution argued that Kasab's surprise confession on Monday, after he had initially pleaded not guilty, minimised his role in the violence and could even have been an attempt to help his mentors awaiting trial in Pakistan.

Evidence from the Mumbai trial could theoretically be used in Pakistan against five members of Islamist group Lashkar-e-Taiba, including the alleged mastermind Zaki-ur-Rehman Lakhvi, prosecutor Ujjwal Nikam told the court.

The judge dismissed that argument but ruled that Kasab's confession would be kept on record and considered by the court "at an appropriate stage".

"I don't think that there is any technical move on the part of accused number one to scuttle the trial with a view to helping his alleged mentors in Pakistan," he ruled.

The trial resumed with further examination of prosecution witnesses.

Scientific evidence from the US Federal Bureau of Investigation would be heard soon, Nikam said.

Nikam has said that the FBI played a "vital role" in linking Kasab, 21, with the nine other gunmen, all of whom died during the attacks. They also examined telephone calls allegedly made to Pakistani handlers during the assault.

The lawyer told reporters outside court that the judge's ruling "totally vindicated" his stance that Kasab's confession should not end the trial.

After the decision, defence lawyer Abbas Kazmi applied to be relieved of his duties, citing his poor relationship with Kasab.

"My client is not having confidence in me," he said. "In such circumstances, I think I should recuse (withdraw) myself."

He later agreed to stay on after the judge opposed his request and Kasab said he had no complaints.

Kazmi was appointed in April, soon after the trial began in disarray and with a previous court-appointed lawyer dismissed over a conflict of interest.

The case, seen as a major test of the Indian justice system, was initially dogged by the issue of who should defend Kasab.

The Mumbai Metropolitan Magistrate Court's Bar Association resolved not to represent him, while some lawyers who said they were willing to take on the case had their homes attacked.

The Hindu nationalist Shiv Sena party even called for Kasab to be executed without trial outside the Mumbai railway station where he and another militant killed 52 commuters and injured more than 100.

Kasab told the court Wednesday that he was ready to accept the death penalty.