Updated

Pakistani officials say an attack, followed by an explosion has hit outside a courthouse in the country's northwest.

Police official Sajjad Khan says one or two gunmen tried to enter the court building but were prevented by the police, which was followed by a big blast on Tuesday. It wasn't immediately clear what caused the explosion.

Senior local government official Tahir Zafar says there are fears of casualties in the incident, which took place in the town of in Tangi in the Charsadda district.

Pakistan has been hit by a series of brazen suicide bombings last week that were claimed by various Islamic militant groups and that killed over 100 people.