A suspected US missile strike on Thursday killed at least five alleged militants in a tribal area in northwest Pakistan known as a Taliban and Al-Qaeda stronghold, local officials said.
The strike was the latest targeting extremists in the lawless tribal areas bordering Afghanistan -- all said to have been launched by unmanned CIA aircraft -- that have raised tensions between Washington and Islamabad.
A local security official told AFP that a CIA drone had fired three missiles in the Karikot area of South Waziristan -- the same spot where eight suspected militants were killed in a US drone strike 10 days ago.
One of the missiles struck a vehicle, killing five people inside, another security official said, adding those killed were known Taliban militants.
The other two missiles hit a hilltop house that was a known militant hideout in the area, but it was empty at the time of the strike, the officials said.
One militant was also wounded, they added.
"We rushed out of our homes," resident Zar Wali told AFP, saying locals had been panicked by the powerful explosions.
Smoke was still billowing from the targeted house, he said.
Pakistan has repeatedly protested to the United States that the strikes violate its territorial sovereignty and deepen resentment among the 160 million people of the nuclear-armed Islamic nation.
President Asif Ali Zardari has promised zero tolerance for such violations, but some officials say there is a tacit understanding between the US and Pakistani militaries to allow such action.
The suspected US strikes have also continued despite a warning by Taliban militants based in tribal territory last month that any more would lead to reprisal attacks across Pakistan.
A US missile attack in November last year killed Rashid Rauf, the alleged Al-Qaeda mastermind of a 2006 transatlantic airplane bombing plot, as well as an Egyptian Al-Qaeda operative, security officials have said.
More than two dozen similar strikes have been carried out since August 2007, killing more than 200 people, most of them militants.
Islamabad has come under increased pressure to quash extremist activity within its borders, with Washington and Kabul saying it has not done enough to stop militants crossing the border to attack US and NATO troops in Afghanistan.
Pakistan rejects those accusations, pointing to its operation against militants in the semi-autonomous Bajaur region bordering Afghanistan. The military says more than 1,500 rebels have been killed there since August.
But operations in Bajaur and the nearby Swat valley, where Taliban-linked militants are waging a violent campaign to institute harsh Islamic law, have been scaled back in recent months.
Last week, senior Pakistani security and defence officials said some troops had been shifted from the tribal areas to the eastern border with India, amid simmering tensions with New Delhi in the wake of the Mumbai attacks.
India has blamed those attacks on the Pakistan-based militant group Lashkar-e-Taiba, which is fighting New Delhi's rule in divided Kashmir.
Any major shift of Pakistani troops out of the tribal areas would likely spark concern in Washington and other Western capitals, as it could open the door to more attacks on foreign forces in Afghanistan.