Pakistan charged seven men on Wednesday in last year's Mumbai terror attacks, its first indictments in a case watched closely by India and the United States to see if Islamabad makes good on promises to punish those responsible.

The indictments before an anti-terrorism court came on the eve of the first anniversary of the attacks on hotels, a train station and other targets in the Indian financial center that terrorized the city for three days and killed 166 people.

The seven suspects pleaded not guilty to charges they helped plan and execute the attacks, defense lawyer Shahbaz Rajput and prosecutor Malik Rab Nawaz said.

The men, allegedly belonging to the Lashkar-e-Taiba militant group, could face the death penalty if convicted. Two of the defendants, Zaki-ur-Rehman Lakhvi and Zarrar Shah, have been accused by India of masterminding the attack.

Later Wednesday in Washington, Indian Prime Minister Manmohan Singh issued a stern warning to Pakistan, saying it must punish the masterminds of the attacks. He said the planners of the attacks are still free in Pakistan.

In the past, Islamabad has failed to punish militants suspected of attacks on targets in its giant eastern neighbor, with which it has fought three wars since independence from Britain in 1947.

The country's security agencies have a long history of supporting Lashkar and other militant groups to use as proxies against the much larger Indian army in the disputed region of Kashmir. The government says it no longer does this, but many powerful Pakistani politicians and army officers are believed to remain sympathetic to groups attacking India.

India is trying the lone surviving gunman, Ajmal Kasab, who also faces the death penalty if convicted.

According to testimony in that trial, the group of 10 attackers landed in Mumbai after setting sail from the Pakistani port city of Karachi. They are alleged to have kept in contact with handlers in Pakistan during the siege via telephone.

Wednesday's indictments come as Pakistan's army wages a major offensive against Islamic militants on its northwestern frontier with Afghanistan - an action welcomed by the United States and other Western nations.

The court proceedings are taking place behind closed doors at a maximum-security prison not far from the capital, Islamabad.

Lawyers for the suspects have said they are unable to disclose any details of the charges against the men.

All the accused categorically told the court they were innocent and the charges leveled against them are not supported by the evidence, Rajput said after the court adjourned until Dec. 5.

India has sent Pakistan dossiers of what it says is evidence linking Pakistani nationals with the attack, included Lashkar-e-Taiba founder Hafiz Mohammed Saeed, who remains free.

The Mumbai attacks halted a peace process between the nuclear-armed rivals which had eased tensions but made slow progress in resolving the Kashmir issue since it began in 2004. India says Pakistan must crack down on militants before it can resume talks.

Singh, speaking a day after an elaborate state visit with President Barack Obama, said the Mumbai attack was a calculated attempt by forces outside our country to destabilize India and undermine its progress.