At least 10 people were killed yesterday in a missile attack by a US aircraft in the northwestern Pakistani region of North Waziristan, a haven for al Qaeda and Taliban militants, a security official said.
The strike, near the town of Miranshah, was the first since a recent surge in tension between Pakistan and the US over how to tackle the Taliban and al Qaeda along the border with Afghanistan.
"Yes, missiles have been fired. We have reports that more than 10 people were killed," a security official said.
Residents said two missiles were fired at a former government school where militants and their families were living in Tool Kheil village, five kilometres east of Miranshah.
An intensifying insurgency in Afghanistan has compounded pressure on Pakistan to go after militants operating from remote enclaves on its side of the border.
It has also led to an increase in missile attacks by US drone aircraft, with about a dozen strikes this year killing scores of suspected militants and civilians.
But in addition to missile strikes, helicopter-borne US commandos carried out a bloody ground assault in Pakistan's South Waziristan last week, the first known incursion into Pakistan by US troops since the 2001 invasion of Afghanistan.
Pakistan condemned the raid.
The US military said on Wednesday it was not winning in Afghanistan and would revise its strategy to combat militant havens in Pakistan. But Pakistani army chief General Ashfaq Kayani said in a strongly worded statement Pakistan would not allow foreign troops onto its soil.
Pakistan's sovereignty and territorial integrity would be defended at all cost, he said, while dismissing speculation of a secret deal allowing US forces to cross the border.
General Kayani said there were no quick fixes to a highly complex militant problem and political reconciliation efforts were also needed.
The New York Times reported on Thursday that President George W. Bush had secretly approved orders in July that for the first time allowed US special forces to carry out ground assaults inside Pakistan without the approval of the Pakistani government. US officials declined to comment on the report and Pakistan's US ambassador Husain Haqqani said Mr Bush had not issued new orders.
Factbox
US military strikes in Pakistan
Tension is growing between the US and its ally Pakistan over how to tackle al Qaeda and Taliban militants as US forces in Afghanistan step up cross-border raids on militants in Pakistan.
US forces have launched about a dozen missile strikes from pilotless drones at militant targets in northwest Pakistan this year killing scores of suspected militants and some civilians.
Here are some facts about the controversy:
Why do Americans conduct cross-border attacks?
Violence in Afghanistan has risen sharply over the past two years as al Qaeda and Taliban fighters have regrouped in remote enclaves in Pakistan's ethnic Pashtun lands on the Afghan border. The US and Afghanistan have for years pressed Pakistan to do more to eliminate the sanctuaries and stop cross-border infiltration. But Pakistani efforts, which have included military offensives and deals, have largely failed. Pakistani analysts say US strikes in Pakistan are also aimed at scoring points before a US presidential election in November.
Does Pakistan allow US strikes on its soil?
Officially, Pakistan forbids all military action by foreign troops on its soil but under former President Pervez Musharraf, Pakistan gave permission for missile strikes, a Pakistani official said, on the understanding the US would inform Pakistan in advance. There has been no indication of any Pakistani permission for incursions by ground troops.
US officials told the New York Times the decision illustrated lingering distrust of the Pakistani military and intelligence agencies and a belief some US operations had been compromised after Pakistanis were given details. Defence Minister Ahmed Mukhtar said in July US officials believed some Pakistani agents had tipped off militants about impending US missile attacks.
Risks for the US and Pakistan
Support for the US-led campaign against militancy is deeply unpopular in Pakistan and more US incursions are likely to complicate problems for Pakistan's new civilian President, Asif Ali Zardari. Like his predecessor, Mr Musharraf, Mr Zardari is a close US ally but as an elected civilian leader he has to pay more heed to public opinion than former army chief Mr Musharraf.
Civilian deaths in US strikes fuel anti-US sentiment, both in the immediate region and in Pakistan in general, which could undermine support for the government, led by Mr Zardari's party. Anger over US strikes could also increase support for religious and conservative parties that take a strong stand against the US.
The Pakistani military fears US strikes could also fuel support for militants and even spark an uprising among Pashtuns, perhaps reviving efforts by Pashtuns to break away from Pakistan.
A breakdown in US ties would complicate economic problems because Pakistan needs US financial assistance. Pakistani foreign reserves have fallen sharply, raising fears it could default on a sovereign bond unless it gets foreign financing.