A suicide attacker clambered into a northwest Pakistan police compound and set off a bomb that killed up to three officers, police and state media said.
The attack took place Monday in the volatile Swat valley where Pakistan's military has been fighting pro-Taliban militants.
The attacker scaled the perimeter wall of a police office near the area's main town of Mingora and blew himself up after police opened fire on him, said Syed Akhtar Shah, deputy inspector-general of Swat police.
"There was an exchange of fire before the bomber exploded himself near the office," Shah said.