A barrage of US missiles killed up to five militants in Pakistan's North Waziristan tribal district on Friday, destroying a vehicle used by Islamist fighters, security officials said.
Pakistani security officials reported the strikes in what is reputedly the country's most impregnable Taliban and Al Qaeda fortress, where US officials want Pakistan to launch a ground offensive to eliminate the militant threat.
They said strikes killed five rebels in Ghar Laley village, 35 kilometres (22 miles) west of Miranshah, the main town in North Waziristan, and close to the Afghan border.
"US drones fired four missiles, targeting a vehicle and a house," a local Pakistani security official said.
"So far five bodies have been recovered," he said. "Taliban have surrounded the area and there are fears the final toll may go up," he said.
The area is a stronghold of Taliban commander Hafiz Gul Bahadur but neither the precise identities of the dead nor whether they included any high-value target was immediately clear.
"The missiles targeted militants fleeing on a motorbike," said another Pakistani security official, putting the death toll at two.
"The area is considered a stronghold of militants, including foreign Al Qaeda fighters," he said.
Washington says wiping out the militant threat in Pakistan's semi-autonomous tribal belt is vital to winning the nine-year war against the Taliban in Afghanistan and defeating Al Qaeda.
Militant networks in North Waziristan are accused of escalating the nine-year war in Afghanistan and US officials want Pakistan to launch a ground offensive in the district to limit the Islamist threat.
The United States does not confirm drone attacks, but its military and the Central Intelligence Agency operating in Afghanistan are the only forces that deploy the unmanned aircraft in the region.
In 2010 the campaign doubled missile attacks in the tribal area with around 100 drone strikes have killed more than 650 people, according to an AFP tally.
Pakistan tacitly cooperates with the bombing campaign, which US officials say has severely weakened Al Qaeda's leadership, but has stalled on launching a ground offensive in North Waziristan, saying its troops are overstitched.