14 people were killed in the northwestern Pakistani region of North Waziristan today in a missile attack by a pilotless US aircraft on suspected militants near the Afghan border, security officials said.
The strike drew condemnation from prime minister Yousaf Raza Gilani.
It was the first such attack since a US commando operation inside Pakistan last week sent tensions soaring between Islamabad and Washington over how to tackle the Taliban and al Qaeda on the Pakistani side of the border with Afghanistan.
Mr Gilani said Pakistan would raise the issue with the United States at diplomatic level.
"We will try to convince the United States...to respect (the) sovereignty of Pakistan - and God willing, we will convince," he told reporters.
Security officials said about 12 people were wounded in the attack near the town of Miranshah in North Waziristan.
Residents said the pilotless aircraft fired two missiles at a former government school where militants and their families were living.
"We confirm a missile attack at around 5.30 in the morning (23.30 GMT on Thursday)...We have informed the government," said military spokesman Major Murad Khan.
The military, apparently reluctant to highlight infringements of sovereignty, has rarely confirmed such attacks.
An intensifying insurgency in Afghanistan has raised US fears about its prospects, seven years after US-led forces ousted the Taliban. That worry has compounded pressure on Pakistan to go after militants operating from enclaves on its side of the border, including in North Waziristan.
Security forces stepped up offensives in two areas in August, the Bajaur region on the Afghan border and the Swat Valley in North West Frontier province.
The security forces killed 40 militants, including foreigners, in clashes in Bajaur today, raising the death toll to about 150 in fighting this week. Two soldiers were also killed and 16 wounded.
Hours after today's missile strike, a roadside bomb hit a security convoy in a nearby village, seriously wounding two soldiers. Soldiers in the convoy opened fire after the blast, wounding four civilians, residents said.
Fears about Afghanistan's future and frustration with Pakistani efforts to tackle the militants have led to more US missile attacks by drone aircraft in Pakistan.
About a dozen strikes this year have killed scores of militants and some civilians.
In addition, helicopter-borne US commandos carried out a ground assault in South Waziristan last week, the first known incursion by US troops into Pakistan since the 2001 invasion of Afghanistan.
Reuters