The clashes erupted in the section of the prison where “thugs” were kept, IRNA cited the official as saying.

The official blamed the fire at the prison seen in videos shared on social media on the prisoners, claiming they set fire to a warehouse there.

“Currently the situation is completely under control and peace is maintained in the prison, and the firemen are extinguishing the fire,” the official added.

Videos shared on social media on Saturday showed smoke rising from the prison. Repeated gunfire as well as anti-government chants could also be heard in the videos.

Many political activists, journalists and dual and foreign nationals are held at Evin prison.

An eyes witness told Reuters: “Roads leading to Evin prison have been closed to traffic. There are lots of ambulances here.”

“Still, we can hear gunshots,” the eye witness said.

Another witness told Reuters: “I can see fire and smoke. Lots of special forces. Ambulances are here too.”

Activists have expressed concern that the lives of prisoners are in danger.

This comes amid ongoing anti-government protests that erupted across Iran since mid-September after Mahsa Amini, a 22-year-old Iranian Kurdish woman, died in police custody.