A suicide bomb blast, targeting a police center, killed at least nine people including four policemen, and injured more than 30 others in northwest Pakistan, police and local media reports said.

The bomb exploded near a police mobile van, which also affected other passing by passenger vehicles in Hangu, a main city in Khyber Pakhtoonkhwa province.

Local sources said that an explosives-laden vehicle ran into the police checkpost. According to Bomb Disposal Squad, about 300 kg explosives were used in the attack.

All the injured persons including 12 women and four policemen were shifted to the city hospital where four policemen succumbed to injuries.

All the police personnel were riding in the police vehicle which came under attack. With the impact of the blast 12 nearby houses also got damaged severely, local residents said.

Security officials reached the site and cordoned off the area and started a search operation.

No group claimed responsibility for the attack. Taliban militants have in the past targeted police.