One officer killed in attack on police station in Iran

State television said two attackers had detonated their explosive belts entrance of the station and a third had gone inside. 

"It is said that one or two policemen have been martyred," a TV correspondent said.

Alireza Marhemati, a top provincial security official, denied suicide bombers were involved. 

"They used grenades to enter and it was not a suicide operation," he told state TV.

Sistan-Baluchistan, bordering Pakistan and Afghanistan, is one of Iran's poorest provinces and a major drug trafficking route. It has seen repeated killings by security forces in recent years.

Human rights groups say the Baluch minority, estimated to number up to two million people, has faced discrimination and repression for decades.