Washington: Indian Prime Minister Manmohan Singh urged the United States Sunday to pressure Pakistan to rein in Islamic extremists as President Barack Obama walked a fine line with the rival nations' leaders.

On the eve of a 47-nation summit on nuclear security, Obama met separately with Singh and Pakistani Prime Minister Yousuf Raza Gilani as part of his administration's efforts to build relations with both countries.

Addressing one sore point in relations, India said Obama promised Singh to give access to David Headley - the US-born son of a former Pakistani diplomat who admitted scouting sites for the bloody 2008 siege of Mumbai.

US prosecutors have promised not to extradite Headley in return for his guilty plea, setting off indignation among Indians who wondered the reaction if the United States were denied access to a culprit of the September 11 attacks.

Indian Foreign Secretary Nirupama Rao, who attended the meeting, said Obama was "fully supportive" of Singh's requests for access to Headley but declined to give a time-frame.

But Rao said that India also wanted the United States to turn up the heat on Pakistan to rein in Lashkar-e-Taiba, the Islamist movement accused of carrying out the Mumbai attacks that left 166 people dead.

Singh told Obama "that unfortunately there was no will on the part of the government of Pakistan to punish those responsible for the terrorist crimes in Mumbai of November 2008," Rao told reporters.

"This is where the partnership of India and the United States could make a difference," she said.

Relations between the United States and India have warmed markedly in the past decade, with US political leaders across the political spectrum embracing an alliance with the world's largest democracy.

Obama last met with Singh in November last year when he gave him the honor of the first state dinner of his presidency.

But the United States also has a growing relationship with Pakistan and the Obama administration has been keen to ease anti-Americanism in the country by showing it is seeking cooperation on issues other than Afghanistan.

Pakistani foreign ministry spokesman Abdul Basit said ahead of Obama's meeting with Gilani that he hoped it "will help accelerate the momentum of relations" after the United States held a first-of-a-kind strategic dialogue with Islamabad last month.

Despite concerns about Lashkar-e-Taiba, the Obama administration has welcomed what it sees as a stronger response by Pakistan in cracking down in other extremist groups including homegrown and Afghan Taliban.
Afghanistan has also been a source of tension between India and Pakistan, which many policymakers in Islamabad fearing its historic rival New Delhi is trying to surround it through its warm relations with President Hamid Karzai.
Rao said that Obama told Singh that he "fully appreciated India's interest in Afghanistan and recognized the enormous sacrifices that India has made" through its development assistance.
Gilani came to the United States newly emboldened as the Pakistani parliament approves laws that strengthen the prime minister and weaken the role of the president, reversing the trend after years of military rule.
State Department spokesman Philip Crowley welcomed the moves, saying: "As a friend of Pakistan, we applaud the efforts taken by Pakistani political leaders to achieve national consensus on political reforms."
India and Pakistan are considered crucial players in the goal of the two-day Washington summit - preventing loose nuclear material from falling into the hands of extremists.
The two nations declared themselves nuclear weapons states in 1998. The United States has welcomed India's record and pursued cooperation but has been concerned about proliferation from Pakistan.