Pakistani police and intelligence officials say a suspected U.S. drone carried out a missile strike Thursday in northwest Pakistan, killing at least six people.
The strike took place outside Pakistan's remote tribal region. The dead reportedly include three senior Afghan militants.
One of the men killed has been identified as Maulvi Ahmad Jan, believed to be a senior adviser to Sirajuddin Haqqani, the chief of what U.S. officials describe as the most feared Afghan group battling foreign troops in Afghanistan along side the Taliban.
The missile attack hit an Islamic seminary in Khyber Pakhtunkhwa province. It is known to be visited by senior members of the Afghan Haqqani network -- one of the most feared militant groups battling U.S. troops in neighboring Afghanistan.
Imran Khan, leader of the Pakistan Tehreek-e-Insaf party, condemned the strike.
"This (drone attack) did not happen in a tribal area. They (the U.S.) were always justifying killing Pakistani citizens by saying that Pakistani authorities have no control in tribal regions and that's why Pakistani forces cannot stop them (militants). But for the first time this attack happened inside the Khyber Pakhtunkhwa settled area."
Khan vowed that his supporters will block NATO supplies on Saturday to protest U.S. drones.