Four members of Iran's Revolutionary Guards were killed in the country's southeast and the killers fled to neighbouring Pakistan after coming under fire, the official IRNA news agency reported on Monday.
IRNA gave no further details about the incident in the Saravan area of Sistan-Baluchistan province, scene of some of the deadliest unrest during Iran's nationwide protests, and a region where security forces clash often with drug smugglers.
Citing a Revolutionary Guards statement, IRNA said three of the dead were members of the Basij, a militia affiliated with the Revolutionary Guards that has been widely deployed during a state crackdown against protesters.
"The perpetrators of attack ... fled to Pakistan after receiving heavy fire," IRNA reported, citing a statement issued by the Guards.
The impoverished Sistan-Baluchistan province is home to the Baluchi minority, an ethnic group which follows Sunni Islam rather than the Shi'ite Islam of Iran's clerical leaders and has long complained of discrimination by the authorities.
The provincial capital, Zahedan, was scene of some of the deadliest unrest during the wave of nationwide protests ignited by Mahsa Amini's death in morality police custody, when security forces killed at least 66 people in a crackdown on Sept. 30, according to Amnesty International.
The unrest, in which demonstrators from all walks of life have called for the fall of Iran's ruling theocracy, has posed one of the biggest challenges to the Shi'ite-ruled Islamic Republic since its 1979 revolution.
A Baluchi militant group, Jaish al Adl, has previously mounted attacks on Iranian security forces in the area. Iranian authorities say the group operates from safe havens in Pakistan.
According to activist HRANA news agency, 502 protesters and 62 members of security forces had been killed as of Dec. 18 during the unrest ignited by Amini's death.
(Reporting by Elwely Elwelly; Writing by Tom Perry, editing by Ed Osmond)
