But the White House firmly disputed Pakistan's account of the call, which described Bush as telling Musharraf that the threats were "unsavoury" and smacked of "electioneering" ahead of the 2008 US presidential election.

Bush's call to his embattled ally in the "war on terror" came after recent statements from US officials, and Democratic presidential hopeful Barack Obama, warning of possible US strikes in Pakistan's tribal areas.

"President Bush stated that the United States fully respected Pakistan's sovereignty and appreciated Pakistan's resolve in fighting al-Qaeda and other terrorist elements," the Pakistani foreign ministry statement said.

"He said that such statements were unsavoury and often prompted by political considerations in an environment of electioneering. He agreed that such statements did not serve the interests of either country," it added.

But a White House official called that description of the telephone call "not accurate" and stressed that Bush "did not say anything about 'unsavoury' or 'electioneering.'"

"He basically talked about 'I know you've heard different things coming out the system, and you need to know we're going to work together to deal with terrorists,'" said the US official, who requested anonymity.

Islamabad has been angered by a string of what it has called "irresponsible and dangerous" warnings by US officials who claim that Pakistan's tribal belt has become a safe haven for Osama bin Laden's al-Qaeda network.

Obama weighed in on Wednesday, saying that if he is elected president he would order US forces to hit extremist targets in Pakistan if Musharraf failed to act. Islamabad called his comment "sheer ignorance."

At the White House, spokesman Gordon Johndroe said Bush had congratulated Musharraf and Pakistan on the upcoming 60th anniversary of the country's independence.

"Both leaders reaffirmed the strong partnership between their two nations and their commitment to work together to fight terrorism," Johndroe said in a statement.

But Bush's administration has also ramped up the pressure.

Senior US State Department troubleshooter Nicholas Burns said last week that Washington would retain the option of targeting al-Qaeda in the Pakistan-Afghan border areas in some circumstances.

A few days earlier the White House's top counter-terrorism official Frances Townsend caused a stir by refusing to rule out a similar military incursion.

The comments have been alarming for a close ally that has received billions of dollars in US military aid since abandoning support for Afghanistan's Taliban movement after the 9/11 attacks on the United States.

On the other hand Musharraf made a fresh pledge on Friday to eradicate Islamic extremism from Pakistan, as the latest incident in a wave of militant violence left four rebels dead.

Military ruler Musharraf, who faces US threats of unilateral action against al-Qaeda insurgents in Pakistan's tribal areas, made the vow at a meeting of chiefs in the garrison city of Rawalpindi, a statement said.

"Extremism and militancy are the biggest threat to security of our country and no effort shall be spared to eradicate this menace and ensure sustainability of economic progress," the statement quoted Musharraf as saying.