PESHAWAR: A US missile strike killed seven militants in Pakistan's tribal district of Khyber on Thursday, local security officials said, in an apparent expansion of America's covert drone campaign.

The United States does not as a rule confirm drone attacks, but its military and the Central Intelligence Agency operating in Afghanistan are the only forces that deploy the aircraft in the region.

Washington considers Pakistan's lawless tribal belt the global headquarters of Al-Qaeda and says eliminating the militant threat is vital to winning the nine-year war against the Taliban in neighbouring Afghanistan.

Pakistani officials said a US drone fired a missile that destroyed a vehicle carrying up to seven militants in the Spin Darang area of the Tirah valley in Khyber, which borders Afghanistan.

“It was a drone attack. Seven militants travelling in the vehicle were killed in the attack,” a security official in Peshawar told AFP.

Another security official said all the dead were local Taliban militants.

They were thought to be from Waziristan, Pakistan's most notorious Al-Qaeda and Taliban hub on the Afghan border, and the northwestern district of Swat, where Pakistan launched a major operation last year to clear out the Taliban.

Pakistani security officials were divided over whether it was the first or second US drone strike in Khyber, close to the teeming northwestern city of Peshawar.

Local media reported a US drone strike in Khyber in May, although Pakistani officials at the time were reluctant to confirm the attack.

A new US policy review on Thursday concluded that President Barack Obama's troop surge has made progress in curbing the Taliban in Afghanistan and severely weakening Al-Qaeda in Pakistan.

The report says that after a relentless US campaign, Al-Qaeda's leadership in Pakistan is weaker than at any stage since the 2001 US-led invasion of Afghanistan after the September 11 attacks.

Progress will permit a “responsible reduction” of US forces in Afghanistan, currently nearly 100,000-strong, to begin next July, though a full handover to Afghan security is not envisaged until at least 2014, the review said.

The report also said that the US anti-terror alliance with Pakistan had been “substantial” but “uneven” in the last year, since Obama vowed to forge a new relationship of mutual trust and respect with Islamabad.

On Thursday, Britain said it was looking into media reports that two British men, possibly Muslim converts, were killed in a US drone strike in Pakistan's North Waziristan region last week.

“Our High Commission in Pakistan is seeking further information on these reports,” a Foreign Office spokeswoman said.

Channel Four News and The Guardian newspaper claimed that the Britons died in a strike near the town of Datta Khel on December 10.

The men were aged 48 and 25 and reportedly had English names but used the pseudonyms Abu Bakr and Mansoor Ahmed.

If confirmed, the men would be the first white British converts to have been killed in the area, The Guardian said.