Officials in Pakistan say they believe an al-Qaida weapons expert was the target of a suspected U.S. missile strike near the Afghan border.
The officials say an Egyptian militant known as Abu Khabab al-Masri may have been one of six people killed in the missile strike Monday.
Al-Masri had a $5 million bounty on his head.
Officials say the missiles hit a house next to a religious school, near the village of Azam Warsak, in Pakistan's South Waziristan tribal region. They say three of the six killed were foreign militants. At least three others were wounded.
People in the area reported hearing the sound of jets or drones before the attack.
NATO and U.S.-led coalition forces in Afghanistan denied carrying out the attack. The U.S. Central Intelligence Agency is also known to operate drones in the region.
At the Pakistani army headquarters in Rawalpindi today, the head of Pakistan's Joint Chiefs of Staff Committee warned the acting commander of U.S. Central Command that cross-border strikes could damage Pakistan's relations with the United States.
Pakistani General Tariq Majid told U.S. Lieutenant General Martin Dempsey that Pakistan's sovereignty and territorial integrity must be respected.
Later, Dempsey handed over four F-16 jet fighter aircraft to Pakistani air force officials. The United States has provided Pakistan 10 other F-16s over the past three years.
Washington provided the aircraft at no cost except for the expenses of preparation and transport from the U.S. to Pakistan.
Some information for this report was provided by AFP and Reuters.