"Whatever I have done, I have done in this world. It would be better to be punished in this world. It would be better than God's punishment. That's why I have pleaded guilty," Ajmal Kasab, a Pakistani, told the court.

Mr. Kasab unexpectedly confessed Monday to taking part in the three-day attack that began Nov. 26, leaving a trail of carnage across downtown Mumbai, India's financial and entertainment capital.

"If I am hanged for this, I am not bothered. I don't want any mercy from the court. I understand the implications of my accepting the crime," he said.

Mr. Kasab, 21, was responding to accusations by Chief Prosecutor Ujjwal Nikam that the Pakistani national was trying to minimize his role in the attack to avoid the death penalty and protect his alleged co-conspirators in Pakistan. Mr. Nikam told the court that parts of his confession were inconsistent with evidence.

Judge M.L. Tahiliyani has yet to accept the confession, which has complicated the already onerous task of defending a man whose photograph showing him striding through Mumbai's main train station with a gun has become an emblem of the terrifying three days.

The confession, which describes in detail his links with a shadowy but well-organized group in Pakistan, also bolsters Indian accusations that Islamabad is not doing enough to clamp down on terrorist groups.

Mr. Kasab said he was not tortured or coerced into making the confession. "If somebody thinks that I have confessed the crime to escape the death penalty, he should take it out of his mind," he said.

In his confession, Kasab spoke of the killings by some of the other gunmen who came with him from Pakistan on a boat and the role their handlers played in instigating them to carry out the attack with provocative videos.

After landing in Mumbai, the 10 gunmen split up into pairs and fanned out to carry out the killings at a railway station, a hospital, a Jewish center and two five-star hotels.

Mr. Kasab's confession goes into detail about the shootings by his partner, Abu Ismail, at the Chhatrapati Shivaji Terminus railway station, where more than 50 people were killed, and at the Cama hospital.

The pair later hijacked a Skoda car, which was stopped by police. In the resulting shootout, Mr. Kasab was injured and captured while Abu Ismail was killed. The other eight gunmen were also killed during the course of the siege.

Mr. Nikam urged the court not to rush to issue a judgment based only on Mr. Kasab's confession, saying only parts of it that are consistent with the prosecution's evidence should be accepted.

"The rest of the things that he has said are so many total lies," he told reporters later.

Mr. Nikam said the court should also allow the prosecution to finish presenting its case so it can expose inconsistencies in Mr. Kasab's confession.

The Mumbai siege severely strained relations between India and Pakistan and slowed a peace process between the nuclear-armed rivals.

Pakistan is trying five alleged members of Lashkar-e-Taiba, the group India says masterminded the attack. The five have denied allegations that they played a role in the Mumbai attack.

In his confession, Mr. Kasab said one of those men, Zaki-ur-Rehman Lakhvi, saw him and the other attackers off on their suicide mission.

Mr. Kasab initially pleaded not guilty to 86 charges including murder and waging war against India, which is punishable by death. He said he made the abrupt about-face because the Pakistani government acknowledged he was Pakistani and began legal proceedings against the alleged masterminds of the Mumbai attack.

Two Indians, Fahim Ansari and Ahmed Sabauddin, also are on trial for allegedly providing maps that helped in the attack.