Explosives have been found at Mumbai's main train station, Indian police have said.

Chhatrapati Shivaji Terminus was one of the sites attacked by militants who killed 171 people in the city last week.

Police said they had found 8kg (18lb) of explosives in a bag left behind on November 26 at the start of a three-day rampage by Islamist militants.

There was no bomb, an official at the train station's police control said.

Meanwhile, US Secretary of State Condoleezza Rice has flown into New Delhi to help ease tensions that have surged between India and Pakistan.

She said: "This is the time for everybody to co-operate and do so transparently, and this is especially a time for Pakistan to do so."

Dr Rice urged Pakistan to move fast to help catch those responsible for the Mumbai attacks.

India has threatened to pull out of a five-year-old peace process between the nuclear rivals if Pakistan fails to act swiftly against those responsible. Indian police believe the militants had trained for more than a year on Pakistani soil.

And Indian Foreign Minister Pranab Mukherjee went further at a meeting with Dr Rice, claiming the attacks were led from inside Pakistan.

Dr Rice warned India that its response to the attacks should not provoke Pakistan. She said: "Any response needs to be judged by its effectiveness in prevention and also by not creating other unintended consequences or difficulties."

Pakistan President Asif Ali Zardari has said he doubted Indian claims that the only surviving Islamist gunman out of the ten who attacked Mumbai was a Pakistani.

Mr Zardari said: "We have not been given any tangible proof to say that he is definitely a Pakistani. I very much doubt ... that he's a Pakistani."

He added that if given evidence his government would take action.

India has long said Pakistan is unable or unwilling to act against anti-India militant groups on its soil.

The latest attacks are threatening to unravel improving ties between the adversaries, who have fought three wars since independence from Britain in 1947.

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