A suicide bomber struck a security checkpoint in North Waziristan, Pakistan, on Tuesday, killing two soldiers, a policeman, and a civilian.
The attack was the second in two days in the northwestern region, which borders Afghanistan.
According to Al Jazeera, a local police official, confirmed that the attack was a suicide bombing. He said the bomber detonated himself during a routine road check.
Several civilians are reported to have been wounded.
No group has claimed responsibility for the attack, but it comes a day after the Pakistani Taliban, known as TTP, claimed responsibility for an assault on an oil and gas plant in the Hangu district of Khyber Pakhtunkhwa. The attack killed four security personnel and two private guards.
The TTP has intensified its attacks in recent months following the unilateral termination of a ceasefire with the Pakistani government.
Pakistan has accused the Taliban in Afghanistan of providing sanctuary to the TTP and threatened direct military action.