A suspected U.S. missile strike killed four alleged insurgents Monday in a militant stronghold near the Afghan border, Pakistani intelligence officials said.
The two officials said a pair of missiles hit a vehicle close to Mir Ali town in North Waziristan.
They spoke on condition of anonymity because they were not authorized to speak to the media on the record.
The area is home to militants from the Afghan and Pakistani Taliban and foreign Islamist fighters.
Pakistan's army has not launched an offensive in North Waziristan, meaning militants there have an effective safe haven.
The U.S. routinely fires missiles at militant targets, drawing Pakistani government criticism.
Also Monday, violence continued in Karachi, the country's largest city, where gunmen killed four more people,
Sharfuddin Memon, a provincial government adviser on security, said the four were gunned down Monday in a busy neighborhood where several key police facilities are located.
Senior provincial medical officer Hamid Parihar said the bodies of 18 people who were shot or tortured to death were brought to government hospitals in Karachi in the past two days.
At least 85 people have been killed in Karachi in the past week.
The city has a long history of violence, with much of the fighting blamed on gangs allegedly linked to political parties.
The Muttahida Qaumi Movement, the city's most powerful political party, said It will observe a general strike to protest the violence Tuesday, urging traders to shut down their businesses and transporters to take vehicles off the road.
Associated Press Writer Ashraf Khan in Karachi contributed to this report.