A US drone fired two missiles into a vehicle in Pakistan's tribal district of North Waziristan on Friday, killing at least three militants in a Taliban and Al-Qaeda stronghold, officials said.

The attack took place in the Kharkamar area, 40 kilometres (25 miles) west of Miranshah, a stronghold of the Taliban and militants linked to Al-Qaeda, whose leader Osama bin Laden was killed by US forces in Pakistan on May 2.

"A US drone fired two missiles targeting a militant vehicle, killing at least three militants," a senior security official told AFP.

It was the fourth such attack reported in Pakistan's tribal badlands on the Afghan border, which Washington has dubbed the global headquarters of Al-Qaeda, since US Navy SEALs killed bin Laden in the Pakistani city of Abbottabad.

The new attack coincided with a joint sitting of parliament in Islamabad, where Pakistan's intelligence chief Ahmad Shuja Pasha and army chief of staff Ashfaq Kayani were briefing lawmakers on the bin Laden operation.

Another local security official confirmed the strike and toll, but said the identities of the dead were not immediately known.

At least five rebels were killed in a similar US strike that targeted a militants' vehicle in the Datta Khel area of North Waziristan on Thursday.

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.

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.

Pakistanis have also been outraged at the perceived impunity of the US raid, while asking whether their military was incompetent or conspired to protect bin Laden, whose Yemeni wife said he lived in Abbottabad for five years.

Under US pressure, Islamabad has ordered an internal military investigation to ask how the Al-Qaeda chief managed to live for years under the nose of its military. The opposition leader has demanded a full, independent inquiry.

But under growing domestic pressure to punish Washington for the bin Laden raid, Pakistan's civilian government said Thursday it would review counter-terrorism cooperation with the United States.

It was unclear if the move was intended as a threat, but it showed the extent of the task facing US Senator John Kerry as he prepares to embark on a mission to shore up badly strained ties with Washington's fractious ally.