KANDAHAR, AFGHANISTAN: An Afghan official says at least four police officers have been shot to death in southern Helmand province.

Gen Aqa Noor Kentoz, provincial police chief, said Saturday that all four had been killed the night before at a checkpoint on the outskirts of Lashkar Gah, the provincial capital.

Kentoz says the four might have been attacked by an insider. An investigation is underway, he says.

No one immediately claimed responsibility, but Taliban have increased their attacks against Afghan security forces across the country.