State TV quoted Gen. Mohammad Mahdia, police chief in western Lorestan province where the shootout took place, as saying the suspects belong to two different groups. He did not elaborate but said an investigation was ongoing.
The report said the shootout occurred near a gas station and that the explosion of the tanker shattered the windows of a nearby building. The killed policeman was identified as Najmeddin Bavi.
State TV said the wounded police officer, Lt. Jaber Beiranvand, was in ICU at a local hospital. The report said the gunmen initially opened fire on the tanker and then on the police who were patrolling the area. The assailants later fled in a stolen car.
Heavily rural Lorestan has seen occasional tribal-related clashes and many people in the area have private firearms.
In November, authorities confiscated some 150 guns from smugglers in the province.
This story has been corrected to show that the name of the province is Lorestan.