At least four road police patrol officers were killed in a "terrorist" attack in the mostly Sunni city of Zahedan in Iran's restive southeast, according to the semi-official Tasnim news agency on Sunday.
A judicial order has been issued to arrest the perpetrators, Tasnim reported.
Zahedan, capital of Sistan-Baluchistan province, which borders Pakistan and Afghanistan, is one of Iran's poorest provinces and a major drug trafficking route.
"Today, attackers ambushed the police car.. and shot at the vehicle," Tasnim report added.
The perpetrators and their motive were not immediately clear.