According to the Tasnim news agency, two gunmen tried to enter the Shah Cheragh shrine and opened fire on visitors.

According to the report, one of the assailants was apprehended, while the other escaped.

In October, another attack claimed by the Islamic State (IS) killed 13 people in Shah Cheragh.

The new incident was not immediately claimed by any organisation.

“Four people have been killed so far as a result of a terrorist attack on the holy shrine by two armed men,” the official Iranian news agency IRNA said.

Meanwhile, the semi-official Fars news agency said that the gunmen attempted to enter the shrine through the Bab al-Mahdi gate but were met with “resistance” by “protection forces.”

According to witnesses, one of the shooters began shooting indiscriminately after being approached by security.

According to Tasnim, another semi-official news organization, at least seven individuals were injured, and stores in the neighborhood were shuttered. Security troops, according to state television, had blocked off the shrine area.

Tasnim photos revealed gunshot holes in what seemed to be barred windows at the shrine’s entrance, one of Iran’s most prominent pilgrimage destinations.

The shrine contains the tombs of the seventh Shia Imam Musa al-Kadhim’s two sons, who are also the brothers of the eighth Imam Ali al-Rida.

Last month, Iran hanged two persons suspected of aiding in the October assault. The main perpetrator, an Afghan national, was slain at the scene of the incident.

Three additional defendants were sentenced to up to 25 years in jail for their participation in the Islamic State organization.

IS has claimed past assaults in Iran, including the devastating twin bombings in 2017 that targeted the country’s parliament and Ayatollah Ruhollah Khomeini’s shrine.