A suicide car bomber targeted a security checkpoint in northwestern Pakistan on Wednesday, killing two soldiers, a policeman and a civilian, the military and security officials said.
It was the second militant attack to hit Pakistan in as many days.
The bombing happened in North Waziristan, a district in Khyber Pakhtunkhwa province that borders Afghanistan and is a former stronghold of the militant Pakistani Taliban group, also known as Tehreek-e-Taliban Pakistan.
A number of civilians were also wounded in the attack, according to Rehmat Khan, a local police official.
Separately, security forces killed six militants in a raid on their hideout in South Waziristan, a district also bordering Afghanistan, the military said Wednesday. It did not provide any details about the slain insurgents, but such operations are usually carried out against the TTP. In the last six months, the group has stepped up its attacks since it unilaterally ended a cease-fire with the Pakistani government, brokered by neighboring Afghanistan last year.
Also on Wednesday, the TTP claimed responsibility for an attack the previous day on an oil and gas plant in Hangu, a district in Khyber Pakhtunkhwa, on the border with Afghanistan. Four security troops and two private guards were killed in the attack on the facility run by a multinational European company, MOL Pakistan Oil and Gas.