ISLAMABAD – Seven people, including two policemen, were killed and several others injured in an explosion targeting a police vehicle in Pakistan's northwestern Khyber Pakhtunkhwa province on Tuesday, police sources said.

The incident happened in Lakki Marwat district, where the blast targeted a police vehicle during routine patrolling in the area, the sources told Xinhua on condition of anonymity.

"The blast happened in a crowded market area, so a large number of civilians passing by the attack site were also killed and injured," the sources added.

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The area has been cordoned off for investigation. A bomb disposal squad reached the site following the explosion, and the nature of the blast is being determined.

The injured were shifted to a nearby hospital. No group has claimed the attack yet.