Tensions between India and Pakistan escalated last night after it was claimed that the only terrorist to have survived three days of deadly battles in Mumbai was from Pakistan, and that his nine fellow Islamist militants were either from that country or had been trained there.

The claims about responsibility for the attack, in which almost 200 people were killed, came from leaked police accounts that gave details of the interrogation of Azam Amir Kasab, 21, said to have been the man pictured at Mumbai's main train station carrying an assault rifle and grenades.

According to the reports, which could not be independently verified, Kasab said that the operation was the responsibility of Lashkar-e-Taiba, a jihadist group based in Pakistan, and its aim was to 'kill as many as possible' in what was intended to be India's 9/11. The claims were made as Indian special forces ended the violent sieges around Mumbai with the killing of the final three terrorists holding out in the Taj Mahal Palace hotel - where British survivors had walked through rooms strewn with bodies and 'blood and guts' as they were led to safety.

The allegations about Pakistan emerged as India was confronted with the full horror of the past few days. Reporters were allowed into the wrecked and scorched remains of the Taj Mahal and Trident-Oberoi hotels, where scores of victims had been murdered.

Public anger in India has been mounting following allegations linking Pakistan to the attacks. They include:

• Kasab's claim that militants were trained in two camps run by Lashkar-e-Taiba in Pakistan.

• Allegations that phones found on a trawler suspected of ferrying the gunmen to Mumbai had been used to contact Pakistan.

• The claim by India's minister of state for home affairs, Sri Prakash Jaiswal, that 'the investigation carried out so far has revealed the hand of Pakistan-based groups in the Mumbai attack'.

In response to the claim that the attackers were either Pakistanis or had been trained there, a senior Pakistani official said troops would be sent to the border if tensions continued to rise.

However, despite initial claims, it became increasingly certain that there was no involvement of British-based fundamentalists. Police forces across the UK denied they were investigating named individuals and Gordon Brown said there was no evidence linking any of the terrorist to the UK.

The escalating war of words between India and Pakistan has set alarm bells ringing in the United States, where President Bush convened an emergency meeting with senior security officials. President-elect Barack Obama, who has said that reconciliation between the nuclear-armed neighbours is essential to stabilise Afghanistan and defeat al-Qaeda, called Indian Prime Minister Manmohan Singh on Friday night to offer condolences.

The cold-blooded intent of the militants has shaken India. Officials said just 10 gunmen, with enough arms and ammunition 'to kill 5,000 people', had attacked the Taj, the Trident-Oberoi, the main railway station, a popular restaurant and a cinema. In the siege of a Jewish centre, which was retaken by security forces on Friday night, the militants had bound and shot five people, including a rabbi and his wife, before they were killed.

A handful of gunmen held out for almost three days, taking hundreds of people hostage, many of them Westerners. Twenty-two of those killed were foreigners. Last night emergency services raised the prospect that many - including three Britons - were still missing from the Taj.

The gunmen set the 105-year-old hotel ablaze as they evaded scores of India's best-trained commandos. They left bodies with grenades stuffed into their mouths.

The photograph of a baby-faced militant, whom newspaper reports claim is Kasab, wearing combat trousers and swinging an AK47 in Mumbai's main railway station, is the defining image of the rampage. His victims are said to include Mumbai's anti-terror squad chief Hemant Karkare, whose body was cremated yesterday.

Under questioning, Kasab is said to have admitted to being a resident of Faridkot in Pakistan's Punjab province. 'I was trained by Lashkar-e-Taiba and asked to cause maximum casualties in Mumbai,' he is alleged to have said, referring to an organisation which India says is sending armed militants into Kashmir. Kasab was arrested on Wednesday night after his partner, said to be Ismail Khan, was shot dead.

The duo's night began when they fired on commuters in the railway station and in two hospitals. Kasab told police that they had learnt about Mumbai's geography using Google Earth.

According to Indian media reports, the captured militant said that a room booked in the Taj had been used to store explosives and ammunition ahead of the attacks. This might explain how the squads of gunmen were able to reload their weapons over more than 50 hours and appeared to have an inexhaustible supply of grenades.

Asif Ali Zardari, the President of Pakistan, yesterday appeared on Indian television in an attempt to defuse tensions. 'As President of Pakistan, if any evidence comes of any individual or group in any part of my country, I shall take the swiftest action in the light of evidence and in front of the world,' he said.

Analysts said that the omens did not look good for the peace process between India and Pakistan. 'I expect a very difficult time ahead,' said Tariq Fatemi, a former Pakistani ambassador to Washington. 'Anything short of a real and genuine effort to co-operate by Pakistan would send very, very bad signals - not just to India but to the US and to Europe too.'