MIRANSHAH: A US drone fired two missiles into a vehicle in Pakistan's tribal district of North Waziristan on Thursday, killing at least seven suspected militants, local security officials said.

It was the third such attack reported in Pakistan's tribal badlands on the Afghan border, which Washington has dubbed the global headquarters of al Qaeda, since US commandos killed Osama bin Laden in a Pakistani city near Islamabad.

“A US drone fired two missiles on a militants' vehicle in the Datta Khel area of North Waziristan,” one Pakistani security official told AFP on condition of anonymity.

“Seven militants were killed,” the official added. Another local official confirmed the strike and the toll, saying: “The target was a pick-up van.”Intelligence reports from the area, which were not confirmed by more senior officials, put the death toll as high as eight and said the dead included “foreigners” - a euphemism for Afghan Taliban, Uzbek militants or al Qaeda.

On Tuesday, a similar strike killed four militants near Angoor Adda village in the neighbouring district of South Waziristan and last Friday eight suspected militants were reported killed by US missiles in North Waziristan.

Washington does not confirm drone attacks, but its military and the CIA operating in Afghanistan are the only forces that deploy them in the region.

The US strikes doubled last year, with more than 100 drone strikes killing over 670 people, according to an AFP tally, and the CIA has said the covert programme has severely disrupted al Qaeda's leadership.

But some experts say the discovery last week of bin Laden living hundreds of kilometres from the tribal area, in the city of Abbottabad two hours' drive from capital, exposes the limits of drone strikes to hit top terror targets.

US officials are now poring over a trove of intelligence obtained in the May 2 helicopter-borne raid on a suburban compound that killed the Al qaeda leader, including a handwritten journal containing his “operational ideas”.

Al qaeda-inspired insurgents in Yemen and Somalia have threatened to avenge the killing and are chillingly warning the West of a bloodier fight to come.

US drone strikes inflame anti-American feeling in Pakistan, which has worsened since a CIA contractor shot dead two Pakistani men in a busy Lahore street in January, and over the perceived impunity of the bin Laden raid.

The surgical operation by US Navy SEALs, seemingly carried out without the knowledge of Islamabad or the country's powerful military leadership, has caused widespread embarrassment in Pakistan.

Prime Minister Yousuf Raza Gilani sought to defend the country in a speech to parliament on Monday, fending off charges of complicity or incompetence over the raid as “absurd” and criticising US “unilateralism” on its soil.