Six people, including a woman and a child, were killed in an attack on the Zahedan judicial centre in Iran's south-eastern Sistan-Baluchestan province, Iranian state news agency Irna reported on Saturday.
Twenty-two other people were injured, it said, citing the Islamic Revolutionary Guard Corps (IRGC) Ground Forces.
The attack on Saturday was carried out by unknown gunmen, the judiciary's Mizan Online outlet said.
The assailants opened fire inside the building in Azadi Street in Zahedan, the semi-official Tasnim news agency said.
"This morning, an armed group attempted to enter the Zahedan courthouse, but the vigilance of law enforcement and security forces prevented them from entering the building and, after that, the terrorists started an armed conflict by using weapons and throwing grenades," the agency quoted the chief justice of Sistan-Baluchestan province as saying.
Irna reported that a number of the injured were in a critical condition.
State media referred to the assailants as "terrorists" and said they were carrying explosive vests. The attackers were killed, Irna added.
The Baloch militant group Jaish Al Adl claimed responsibility for the attack, Tasnim reported.
Jaish Al Adl wants independence for Iran’s eastern Sistan and Pakistan’s south-western Balochistan provinces.
The Sistan-Baluchestan province, bordering Afghanistan and Pakistan, has been the site of occasional deadly clashes involving militant groups, armed drug smugglers and Iranian security forces.
In October, an attack on an Iranian police convoy in the province killed at least 10 officers.
The head of Zahedan University of Medical Sciences, Dr Mohammad Hassan Mohammadi, said emergency services responded to the incident and carried out "diagnostic and surgical procedures" on the wounded.
Visitors were evacuated, Tasnim reported.
