A grenade attack and gun battle in Iran’s southeast near Pakistan left four assailants and two Iranian policemen dead on Saturday, local media said.

It was the latest violence in Sistan-Baluchistan province, where unrest has involved drug smuggling gangs, rebels from the Baluchi minority and Sunni Muslim extremist groups.

There was no immediate indication of who carried out the attack.

“Four unidentified armed individuals attacked and entered police station Number 16 of Zahedan”, the provincial capital, according to state broadcaster IRIB. It quoted the province’s deputy head of security Alireza Marhamati.

The attackers used grenades to blast open the gates of the police station, and an exchange of fire occurred, said Marhamati.

Two policemen were killed in the ensuing clash, according to Tasnim news agency, which quoted Sistan-Baluchistan Police Chief Doustali Jalilian.

All four “terrorists” involved in the attack were killed, according to Iran’s official news agency IRNA, which quoted a branch of the Iranian Revolutionary Guard Corps which commands southeast Iran.

Meanwhile, Pakistan said it “strongly condemns the terrorist attack” and expressed “deepest condolences” to the bereaved families while praying for the swift recovery of the injured.

“Pakistan stands in complete solidarity with the government and people of Iran in this common fight against the scourge of terrorism,” the Foreign Office said in a statement after the attack.

May attacks

In May, five Iranian border guards were killed during clashes with an armed group in Saravan, southeast of Zahedan, in one of the province’s deadliest attacks in months.

State media reported at the time that the attack was carried out by “a terrorist group that was seeking to infiltrate the country” but whose members “fled the scene after suffering injuries”.

Zahedan was also the scene of protests that flared in September, with dozens of deaths, over the alleged rape of a teenage girl by a police officer.

In late May, IRNA quoted a police official, Qassem Rezaee, as saying “Taliban forces” had shot at an Iranian police station in Sistan-Baluchistan, a drought-parched region which also borders Afghanistan. The two countries have been arguing over water rights.

Iranian police did not give details of casualties in that incident but local news agency Mehr reported one Iranian border guard had been killed.

Afghanistan’s ruling Taliban said one person was killed on each side.