The ambush took place on Sunday afternoon in western Farah province, Dadullah Qaneh, a member of the provincial council, says. Four policemen, including the deputy provincial police chief, were wounded in the attack near Lash wa Juwayn district.
No group immediately claimed responsibility for the bombing but the Taliban have a strong presence in the province, especially in Bala Buluk where they often plant roadside bombs to target government officials or Afghan security forces.
Taliban fighters attacked the Afghan troops who had assembled to prepare an attack in the western province of Farah in the night, setting off a fierce battle, officials said. An air strike was called in and killed at least 25 militants, he said.