ISLAMABAD U.S. drone aircraft fired missiles into a house in Pakistan's North Waziristan region on Friday, killing at least eight suspected militants just as Islamists protested against the killing of Osama bin Laden.
It was the first drone strike since U.S. special forces killed the al Qaeda leader on May 2 not far from Islamabad, further straining ties between the strategic allies.
About 1,500 Islamists demonstrated against bin Laden's killing, saying more figures like him would arise to wage holy war against the United States.
Pre-dominantly Muslim Pakistan has yet to see any major backlash after U.S. forces killed bin Laden early on Monday in the Pakistani garrison town of Abbottabad.
But his death has angered Islamists, with one major hardline political party calling on the government to end its support for the U.S. war on militancy.
"Jihad (holy war) against America will not stop with the death of Osama," Fazal Mohammad Baraich, a cleric, said amid shouts of "Down with America" at a demonstration near the city of Quetta, capital of Baluchistan province in the southwest.
"Osama bin Laden is a shaheed (martyr). The blood of Osama will give birth to thousands of other Osamas."
Some protesters burned American flags.
Anti-American sentiment runs high in Pakistan, despite billions of dollars in aid for the nuclear-armed, impoverished country.
Pakistan's religious parties have not traditionally done well at the ballot box, but they wield considerable influence on the streets of a country where Islam is becoming more radicalized.
The United States war on militancy is unpopular in Pakistan because of the perception of high civilian deaths from drone attacks against suspected militants along the Afghan border and the feeling they are a violation of the country's sovereignty.
The Pakistani government said bin Laden's death was a milestone in the fight against militancy although it objected to the raid on him as a violation of its sovereignty.
Suspicion that some Pakistani security forces might have known bin Laden was hiding in the country has threatened to strain ties between the allies.
Pakistan has denied any knowledge of the al Qaeda leader's whereabouts and the army threatened on Thursday to cut intelligence and military cooperation with the United States if it mounted more attacks.
Pakistani cooperation is seen as crucial for efforts to end the war in neighboring Afghanistan.
(Reporting by Gul Yousafzai in Quetta, Haji Mujtaba in North Waziristan; Writing by Augustine Anthony; Editing by Michael Georgy and Robert Birsel)