A US drone strike on Friday killed three Taliban fighters in Pakistan's tribal badlands bordering Afghanistan, blowing their vehicle into a ball of flames, local officials said.

It was the first deadly missile strike in a week and comes as Washington appeared to ease pressure on Islamabad demanding action against the Al-Qaeda-linked Haqqani network based in the North Waziristan tribal district.

The militants were killed in Baghar village of neighbouring South Waziristan, where the Pakistan military carried out a sweeping offensive against homegrown militants in late 2009.

"A US drone fired two missiles at a vehicle and at least three militants were killed," a senior Pakistani security official told AFP on condition of anonymity because he was not authorised to talk to media.

At least two other Pakistani intelligence officials confirmed the drone strike and the death toll.

The dead were identified as Pakistanis who fought under a nebulous Taliban umbrella, on behalf of Pakistani warlord Maulvi Nazir, whose fighters are allied to the Haqqanis and active in the 10-year war in Afghanistan.

One Pakistani official said a deputy to Nazir, named Haleem Ullah, was among the dead. The official said he was among those militants who had escaped survived a drone strike in South Waziristan three days ago by escaping.

The tense partnership between Pakistan and the United States in the war on terror took a further battering this month, with Washington demanding that Islamabad take action against the Haqqani network and cut ties to the group.

The outgoing top US military officer Admiral Mike Mullen, called the Haqqani network a "veritable arm" of Pakistan Inter-Services Intelligence (ISI) agency and accused Pakistan of supporting attacks on US targets in Afghanistan.

Islamabad officially denies any support for Haqqani activities, but has nurtured Pashtun warlords for decades as a way of influencing events across the border and offsetting the might of arch-rival India.

The Pakistani military says it is too over-stretched fighting local Taliban to acquiesce to American demands to launch an offensive against the Haqqanis, a battle that not all observers think the Pakistani military would win.

Stepped up US drone strikes is the most probable alternative American course of action, local analysts say.

The United States does not publicly confirm the drone campaign, but are the only forces that deploy the unmanned Predator aircraft in the region.

Around 30 drone strikes have been reported in Pakistan since elite US forces killed Al-Qaeda chief Osama bin Laden near Pakistan's main military academy in Abbottabad, close to the capital, on May 2.

The raid humiliated Pakistan but is thought to have contributed to debate within the military about the merits of traditional support for jihadi groups.

On Thursday, US Secretary of State Hillary Clinton said Washington wants to work to put its relationship with Pakistan on a stronger footing.

At a rare conference in the capital Islamabad, Pakistan sought to deflect US pressure by gathering together more than 50 military commanders and politicians, and saying dialogue was the best way of easing tensions.