A foreign ministry official, speaking on condition of anonymity on Sunday, said that India had told Pakistan that "the environment is not conducive" to talks due to be held in New Delhi on Thursday and Friday.

A series of explosions in commuter trains in the country's financial hub killed 179 people and wounded hundreds more last week.

Indian officials suspect the Pakistan-based Islamist militant group Lashkar-e-Taiba to be behind the attacks.

There has yet to be a breakthrough in the investigations into the bombings.

There was no immediate reaction from Pakistan on the cancellation of talks.

The meeting in New Delhi was to be between the countries' chief foreign ministry officials and was to have reviewed progress in the peace talks, started in early 2004.

Denial

The decision to put off the talks, however, was not an end to discussions, the official said.

"We are still committed to making peace with them. But they have to show that they can keep their promises to end terrorism before we can move forward," he said.

The official was referring to a pledge that Islamabad made in 2004 that it would not allow its territory to be used by anti-Indian militants fighting against New Delhi's rule in the disputed Himalayan region of Kashmir.

Pakistan has denied any connection with the Mumbai bombings and said Indian allegations were nothing more than propaganda or speculation unless New Delhi came up with evidence.

Pervez Musharraf, the president of Pakistan, has offered his country's full co-operation in any investigation by India, wherever it should lead.