The unidentified assailants struck two units on patrol near the town of Iranshahr in Sistan-Baluchistan province, the Fars news agency said, citing local police.
“In this terrorist act, five servants of security and peace were martyred,” it quoted police as saying.
Police said the officers had been on routine patrol when they came under fire. Iranian media published an image of a bullet-riddled police pickup with bodies lying on the ground nearby.
An operation was underway to “track down and identify” the assailants, Fars said.
Later, Jaish al-Adl claimed responsibility for the attack, in a post on the Telegram messaging app.
The latest attack comes after authorities said the security forces had killed seven members of another armed group, Ansar al-Furqan, last week as they foiled an attempted attack. A day earlier, a police officer was killed in an attack later claimed by Jaish al-Adl.