ISLAMABAD - A suspected U.S. drone aircraft fired missiles in the North Waziristan tribal region of Pakistan killing at least four people, according to Pakistani intelligence officials.
The attack on a house near the town of Mir Ali came just two days after Pakistan lodged a protest with the U.S. ambassador over missile attacks on its territory.
"According to our information two missiles were fired by the drone on a house... Four people were killed," an intelligence officer in the region said. Another officer said three missiles were fired.
Villages around Mir Ali have been targeted by missile attacks several times, and Taliban and al Qaeda activity in the area has been traced before.
Pakistan is bristling over a series of missile strikes by U.S. drones targetting al Qaeda and Taliban militants in the lawless tribal regions along the Afghan border in recent weeks.
There have been at least 20 strikes in the last three months, reflecting U.S. impatience over militants from Pakistan fuelling the Taliban insurgency in Afghanistan and fears that al Qaeda fighters in northwest Pakistan could plan attacks in the West.
Pakistan says the attacks violate its sovereignty, undermine efforts to win public support for the fight against militancy, and make it harder to justify the U.S. alliance.
The attack on Wednesday that sparked the diplomatic protest was unusual in that it took place deeper in Pakistani territory, in Bannu district, an area outside the semi-autonomous tribal lands bordering Afghanistan where most other attacks have focused.
An Arab killed in the attack in Bannu was identified by a Pakistani intelligence officer as a known al Qaeda operative, Abdullah Azam al-Saudi, though there has been no other corroboration.
An earlier diplomatic storm blew up after a U.S. commando raid in early September, and there has been no incursion by ground troops since.