A suicide bomber riding in a vehicle targeted a security checkpoint in northwestern Pakistan, killing at least three soldiers and a 10-year-old boy and wounding 14 other civilians, officials have said.

The bombing occurred on Wednesday in Miran Shah, a town in Khyber Pakhtunkhwa province that borders Afghanistan and is a former stronghold of the militant group Tehrik-i-Taliban Pakistan (TTP).

At least 14 civilians and some soldiers were wounded in the attack, according to Rashid Khan, a police official. He said security forces were searching the area for the bomber’s handlers.

Khan initially said two soldiers and a 10-year-old boy identified as Mohammad Qasim were killed, and he later added that a critically wounded soldier died of his injuries, bringing the death toll to four.

Hours after the bombing, the military said three soldiers were "martyred" in the attack.

No one immediately claimed responsibility for the attack, but suspicion is likely to fall on the outlawed TTP.