A fire ripped through an infamous prison in Iran amid reports of heavy gunfire that left eight injured.
Evin prison houses Tehran's political prisoners as videos shared on social media show black smoke billowing from the facility. It is unclear how the fire started.
Other videos show "regime enforcers on motorcycles" racing toward the prison as residents were shouting "death to the dictator".
State media quoted a security official blaming "criminal elements" for the unrest. The official said calm had returned.
At least eight people were injured at Iran's Evin prison fire on Saturday, Iran's state news agency IRNA reported.
One witness told Reuters: "Roads leading to Evin prison have been closed to traffic. there are lots of ambulances here. Still we can hear gunshots."
Activist website 1500tasvir reported: "Gunshots can be heard from Evin Prison and smoke can be seen".
One witness told Reuters: "Families of prisoners have gathered in front of the main door of Evin prison. I can see fire and smoke. Lots of special forces. Ambulances are here too."
The first reports of gunfire were at 7.30pm local time as protests continue to sweep across Iran.
Protests first broke out last month after Mahsa Amini, 22, died while being held in "inappropriate attire".
Protests have widened to strikes as shops and businesses closed in response to the country's religious rule.
The protests have turned violent and in some cases deadly.
The Iranian activist news agency HRANA said on Saturday that 233 people had been killed in the unrest, including 32 minors and 26 members of the security forces.
More than 7,000 had been arrested in protests in 112 cities and towns and some 70 universities, it said in a posting online.
The prison is nicknamed "Evin University" because of the number of students and intellectuals housed there.
Evin prison has been accused of committing "human rights abuses" in the past. Recently an activist said his legs were broken by the guards while he was being held at Evin Prison, Radio Free Europe reported.
Human Rights Watch has accused authorities at the prison of using threats of torture and of indefinite imprisonment, as wellas lengthy interrogations and denial of medical care for detainees.
Evin prison was built in 1972 and is located at the foot of the Alborz mountains.
The grounds of the prison include an execution yard, a courtroom, and separate blocks for common criminals and female inmates.
It was initially designed to house 320 inmates - which included 20 solitary confinement cells and 300 in two large blocks.
However, it was expanded to hold more than 1,500 prisoners including 100 solitary cells.
