Gunmen killed five citizens in a "terrorist attack" on a judiciary building in southeastern Iran on Saturday before being slain by security forces, state media said.

"Unknown assailants attacked the judiciary centre in Zahedan," the capital of southeastern Sistan-Baluchistan province, the judiciary's Mizan Online reported.
 
"Five individuals were killed and 13 others were injured in the terrorist attack," it said, adding that the numbers were "preliminary" and the death toll could increase.
 
In a separate report, three attackers were killed during the attack, according to the regional headquarters of the Islamic Revolutionary Guard Corps.
 
The attackers attempted to go into the building posing as visitors, Alireza Daliri, deputy commander of police in Sistan-Baluchistan province, said.
 
The assailants tossed a grenade inside the building, said Daliri, killing several individuals inside, including a one-year-old baby and the mother.
 
Iranian media said Jaish al-Adl (meaning "Army of Justice" in Arabic), a Baloch jihadist organisation that operates from Pakistan but is also active in Iran, took responsibility for the attack.
 
The province, some 1,200 kilometres southeast of the capital Tehran, borders Pakistan and Afghanistan for a long distance.

The area has seen recurring fighting between Iranian security forces, including the Islamic Revolutionary Guard Corps, and insurgents from among the Baluch minority, extremist Sunni factions, and narcotics traffickers.
 
In one of the deadliest events in the area, ten police officers were murdered in October in what officials also called a "terrorist" attack.