The Wednesday attack was the first such attack since a May 11 general election in which the use of the unmanned aircraft was a major issue. 

A Pakistani Foreign Ministry official condemned all such strikes. 

"Any drone strike is against the territorial integrity and sovereignty of Pakistan and we condemn it," the official, who declined to be identified, told Reuters. 

Pakistani security officials and Pashtun tribesmen in the northwestern region said the drone fired two missiles that struck a mud-built house at Chashma village, 3 km (2 miles) east of Miranshah, the region's administrative town. 

They said seven people were killed and four wounded. It was not immediately clear if the victims were the intended targets. 

"Tribesmen started rescue work an hour after the attack and recovered seven bodies," said resident Bashir Dawar. "The bodies were badly damaged and beyond recognition." 

Prime Minister-elect Nawaz Sharif said this month that drone strikes were a "challenge" to Pakistan's sovereignty. 

"We will sit with our American friends and talk to them about this issue," he said. 

The strike also coincided with the first session of the newly elected provincial assembly of Khyber Pakhtunkhwa, the former Northwest Frontier Province. 

Former cricketer Imran Khan's Pakistan Tehrik-e-Insaf party won most seats in the assembly and has been very critical of drone strikes in the region.