A suicide bombing targeted the administrative headquarters of a tribal region in northwestern Pakistan on Wednesday, killing three policemen and two passers-by, officials said.
The explosion went off at the main gate of the tribal headquarters in Ghalanai in the Mohmand tribal region, just as the workday was about to start, said Hameedullah Khan, a local government official.
No one immediately claimed responsibility for the attack.
Khan, whose office is inside the compound, said the grounds are home to residences, offices and training facilities for the local administration and police employees. Hundreds of local residents come daily on business to the tribal headquarters, located 45 kilometers (28 miles) outside Peshawar, the provincial capital.
The bombing was followed by gunshots, Khan added. The Pakistani army said the bomber was accompanied by another militant, who tried to force his way into the compound after the explosion went off but that security guards opened fire and killed him.
The army statement said there was a higher level of vigilance among the local security forces following intelligence that would-be attackers had infiltrated the area from neighboring Afghanistan.
Wednesday's attack, and another suicide bombing that killed 13 in the eastern Pakistani city of Lahore on Monday, reflect an uptick in militant attacks after almost a three-month lull.
A breakaway faction of the Pakistani Taliban — the Jamaat-ul-Ahrar or Freedom Movement — claimed the Lahore attack. Seven police officers died in that bombing, including a former chief of the province's counter-terrorism department.
The breakaway Taliban faction is based in the Mohmand area — part of rugged, lawless regions along the Afghan border which have long served as safe havens for local and al-Qaida-linked foreign militants, who have killed tens of thousands of people in over a decade.
Pakistan has waged several offensives against militants in recent years.