An Afghan official says the police chief of a volatile district in the country's south has been killed by a roadside bomb.

Helmand provincial police chief Nabi Jan Malakhail, says the explosion happened early Thursday, as Hikmatullah Akmal was heading toward a Taliban attack on a checkpoint in Gereshk district.

He says Akmal's car hit a bomb planted by insurgents on the road leading to the checkpoint.

A major military operation is underway to drive Taliban insurgents from the poppy-rich valley of the Helmand River.

The insurgents, fighting to protect supply routes and a major source of funding from the opium produced in the province, have stepped up attacks on police checkpoints and other government targets.