Police commander Ghulam Sakhi Ghafori says two Afghan police officers and one soldier were killed today in the attack in Helmand province.
He says six others, including one civilian and five soldiers, were wounded in the attack, which occurred on the outskirts of Lashkar Gah, the capital of Helmand.
No one immediately claimed responsibility for the attack, but the Taliban have step up their attacks against both Afghan and foreign forces across the country as most international troops are preparing to withdraw at the end the year.