Condoleezza Rice, the US Secretary of State, met Pakistani government and army leaders today and secured a pledge that they would take strong action against anyone involved in last week's attack on Mumbai.

The assurance was unlikely to satisfy India, which blames Pakistan-based militants for the attack, but diplomats said it would reduce the immediate threat of another military confrontation between the nuclear-armed neighbours.

Dr Rice held talks with Asif Ali Zardari, the Pakistani President, and Yousaf Raza Gilani, the Prime Minister, to try to persuade the weak civilian government to co-operate with India's investigation into the attack.

She also met General Ashfaq Kayani, the powerful army chief, to push the same message, while also urging him not to pull back Pakistani troops fighting Islamist militants near the Afghan border.

In a diplomatic balancing act, Dr Rice flew to Pakistan from India, where she had appealed for restraint in meetings with Manmohan Singh, the Indian Prime Minister, and other political leaders yesterday.

Before leaving Delhi, she compared notes over breakfast with Admiral Mike Mullen, chairman of the US Joint Chiefs of Staff, who was in Pakistan yesterday and is meeting Indian leaders today.

"Everybody wants to prevent further attacks," Dr Rice told a news conference at a military airfield before leaving Pakistan.

"Pakistan, the Pakistani leadership, understands the importance of doing that, particularly in rooting out terrorism and rounding up whoever perpetrated this attack," she said.

India, increasingly backed by US intelligence officials, has blamed the Mumbai attacks on Lashkar-e-Taiba (LeT), a Pakistan-based militant group, and demanded that Pakistan extradite 20 terror suspects.

Mr Zardari, however, has refused to comply and said he doubts the one captured militant is Pakistani.

The standoff has raised fears that India could respond by massing troops on Pakistan's border, as it did after LeT militants attacked the Indian parliament in 2001, almost sparking a fourth war between the two countries.

Pakistan has warned that if that happens again, it would immediately pull back troops from tribal areas near the Afghan border, potentially jeopardizing US and Nato military operations in Afghanistan.

Under pressure from Dr Rice, Mr Zardari softened his stance a little today, saying he had asked India to see this as a chance to work together.

"The government will not only assist in investigations but also take strong action against any Pakistani elements found involved in the attack," a statement quoted him as saying.

"Pakistan is determined to ensure that its territory is not used for any act of terrorism."

Diplomats and analysts say the burden of responsibility is now on Indian investigators, who are being helped by the FBI, to provide solid evidence to back up its assertion that LeT was behind the Mumbai attacks.

Two senior Indian officials said today that they suspected two senior LeT leaders, Zaki-ur-Rehman Lakhvi and Yusuf Muzammil, had orchestrated the attacks and were currently in Pakistan.

They identified Lakhvi as the group's operations chief and Muzammil as its operations chief in Kashmir and other parts of India.

They said the one captured militant had told police he was recruited for the operation by Lakhvi and that the gunmen had called Muzammil on a satellite phone after hijacking an Indian vessel en route to Mumbai.

LeT was banned in Pakistan in 2002 after being blamed for the attack on the Indian parliament, but Indian security officials say it continues to operate under the name of Jammat-ud-Dawa (JuD).

The head of JuD is Hafiz Saeed, the founder of LeT and one of the 20 people that India wants extradited from Pakistan.

The United States added JuD to its list of foreign terrorist organisations in 2006 and froze Mr Saeed's assets this year, but Pakistan has only put it on a watch-list so far and Mr Saeed still regularly addresses large crowds in public.

Pakistan's government is now under pressure to shut down JuD too, but fears that doing so would make it look weak and provoke widespread anger among the organisation's many supporters.

JuD allowed reporters to visit its headquarters in the town of Muridke, just outside the eastern city of Lahore, today in an attempt to demonstrate that it is a peaceful, law-abiding charity.

Abdullah Muntazir, a spokesman for JuD, said after a tour of the complex, which houses two schools, an Islamic seminary, a mosque and other facilities: “All the allegations against us are baseless.”

He condemned the Mumbai attacks as “un-Islamic" and denied that JuD had any links with LeT, but said that he supported LeT's violent campaign against Indian rule in Kashmir.

"We speak loudly. We let the general public know that India is the enemy," he said. "So they are making propaganda and trying to make the government shut this place."

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