NEW DELHI, INDIA - Secretary of State Condoleezza Rice arrived in New Delhi on Wednesday as part of urgent U.S. efforts to ease tension between India and Pakistan that has surged over the Mumbai attacks.

Pakistan President Asif Ali Zardari said he doubted Indian claims that the only surviving Islamist gunman out of the 10 who attacked Mumbai was a Pakistani.

"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," Zardari told CNN's "Larry King Live," adding that if given evidence his government would take action.

At least 171 people were killed in the three-day rampage in India's financial capital that ended on Saturday. Mumbai police on Wednesday said there had been some duplication in counting bodies that put the toll initially at 183.

Rice, who cut short a trip to Europe to come to New Delhi, made no comments to reporters when she arrived.

In other efforts to ease tensions between the nuclear-armed rivals, the top U.S. military commander was visiting the region.

India has long said Pakistan is unable or unwilling to act against anti-India militant groups there. The latest attacks risk unraveling improved ties between the adversaries, who have fought three wars since independence from Britain in 1947.

WHAT USE INTELLIGENCE?

Organized through text messages, mass emails and Facebook, a large protest is planned in Mumbai on Wednesday night by residents more angry at what they see as a huge government security failure than Pakistani involvement.

Advertising executive Sunil Agarwal, 42, said India's intelligence apparatus should be disbanded.

"What use do we have for them? Look at the U.S. after 9/11. There have been no more attacks. That's because their security apparatus is so effective. Their politicians value human life. Ours don't," he told Reuters.

With an election due by May, Indian Prime Minister Manmohan Singh is under pressure to craft a muscular response to opposition criticism, which has intensified since the attacks, that his ruling Congress party coalition is weak on security.

Mumbai's police chief Hasan Gafoor said the attackers had trained for a year or more in commando tactics. Azam Amir Kasav, the only surviving gunman, told investigators he is a Pakistani citizen from Punjab, Gafoor said.

Other investigators have said the gunmen were all Pakistanis, from the Lashkar-e-Taiba group.

Indian Foreign Minister Pranab Mukherjee said military action was not being considered but later warned that a peace process begun in 2004 was at risk if Pakistan did not act decisively.

"Of course the atmosphere has been vitiated. Can't you see the outrage of the Indian people? Am I to explain it? Every Indian feels hurt, feels injured. Is it a conducive atmosphere?" Mukherjee told CNN/IBN television.

The deterioration could also put U.S. counter-terrorism efforts in the region at risk -- Islamabad has said the tensions may force it to shift troops from operations against al Qaeda militants on the Afghanistan border to the frontier with India.

Navy Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, would also visit the region starting on Wednesday, officials said. They declined to give specific details.

India and Pakistan were on the brink of a fourth war in 2002, just a few years after both demonstrated nuclear weapons capabilities, following an attack on India's parliament by Islamist militants.

They pulled back after frantic diplomacy by the United States and other allies.

On Monday, New Delhi renewed a long-standing demand for about 20 fugitives it believes are hiding in Pakistan, a Muslim nation carved from Hindu-majority India in 1947.

Islamabad has said it is battling the same kind of enemy at home. In the past year, hundreds of people have been killed in militant attacks across Pakistan, including a September suicide bombing which destroyed the Marriott hotel in Islamabad.

U.S. officials say the Mumbai attacks bear the hallmarks of operations by Pakistan-based groups such as Lashkar-e-Taiba and Jaish-e-Mohammed, both of which have fought Indian rule in Kashmir. --REUTERS