Fire and clashes at Iran's Evin prison amid Mahsa Amini protests

A fire and clashes erupted at Tehran's notorious Evin prison Saturday night as the protest movement sparked by Mahsa Amini's death in custody entered a fifth week.

The facility in northern Tehran is infamous for the ill-treatment of political prisoners and also holds foreign detainees. Hundreds of those detained during the demonstrations over Amini's death have reportedly been sent there.

Flames and a plume of smoke could be seen billowing into the night sky and the sound of what appeared to be gunfire could be heard in video footage shared by the Oslo-based Iran Human Rights on Twitter.

"A fire is spreading in Evin prison" and an "explosion was heard" from the facility, the 1500tasvir social media channel that monitors protests and police violations said on Twitter.

Chants of "Death to the dictator" -- one of the main slogans of a month-long protest movement that has flared over the death of Amini -- could be heard in the background of the video.

Amini, 22, died on September 16, three days after falling into a coma following her arrest by Iran's notorious morality police over an alleged breach of the Islamic republic's strict dress code for women.

Iranian state media, citing a senior security official, said that "troubles and clashes took place on Saturday night" in the facility and that "rioters" had started a fire.

"The situation is currently completely under control," the IRNA news agency said, reporting at least eight injured.

Evin prison holds foreign inmates including French-Iranian academic Fariba Adelkhah and US citizen Siamak Namazi, whose family said he was taken back into custody this week after a temporary release.

Reacting to reports of the fire, Namazi's family said in a statement to AFP shared by their lawyer that they were "deeply concerned" and had not heard from him.

They urged Iran's authorities to grant him "immediate" means to contact his family and to grant him a furlough "as he clearly isn't safe in Evin Prison."

The sister of another US citizen held at Evin, businessman Emad Shargi, said his family was "numb with worry" in a Twitter post.

US State Department spokesman Ned Price said Washington was monitoring the incident "with urgency", warning that Iran was "fully responsible for the safety of our wrongfully detained citizens" and calling for their quick release.

Award-winning dissident Iranian filmmaker Jafar Panahi and reformist politician Mostafa Tajzadeh are also reportedly held at Evin.

"Shots are being fired while Evin burns," Roham Alvandi, an associate professor of London School of Economics, said on Twitter.

"If, God forbid, political prisoners perish, then this will be an event on the scale of the Cinema Rex fire in Abadan in August 1978 that accelerated the downfall of the shah."

The arson attack at the Cinema Rex, one of the deadliest terror attacks in history before September 11, 2001, stirred protests against the shah's regime although responsibility has never been clear.

Some 400 people died in the inferno at the cinema, whose doors had been locked shut, on the eve of Iran's 1979 Islamic revolution.

Rights groups reported protests in solidarity with Evin detainees in Tehran late into the night, after angry demonstrators had taken to streets across Iran on Saturday despite internet cuts.

Young women have been at the forefront of the current wave of street protests, the biggest seen in the country for years.

"Guns, tanks, fireworks; the mullahs must get lost," women without hijabs chanted at a gathering at Tehran's Shariati Technical and Vocational College, in a video widely shared online.

Scores of jeering and whistling protesters hurled projectiles at security forces near a landmark roundabout in Hamedan city, west of Tehran, in footage verified by AFP.

Despite what online monitor NetBlocks called a "major disruption to internet traffic", protesters were also seen pouring onto the streets of the northwestern city of Ardabil, in videos shared on Twitter.

Shopkeepers went on strike in Amini's hometown Saqez, in Kurdistan province, and Mahabad in West Azerbaijan, said 1500tasvir.

There had been an appeal for a huge turnout for protests on Saturday under the slogan "The beginning of the end!"

"We have to be present in the squares, because the best VPN these days is the street," activists declared, referring to virtual private networks used to skirt internet restrictions.

At least 108 people have been killed in the Amini protests, and at least 93 more have died in separate clashes in Zahedan, capital of the southeastern province of Sistan-Baluchestan, according to Iran Human Rights.

The unrest has continued despite what Amnesty International has called an "unrelenting brutal crackdown" that has included an "all-out attack on child protesters" -- leading to the deaths of at least 23 minors.

A Revolutionary Guards commander said Saturday that three members of its Basij militia had been killed and 850 wounded in Tehran since the start of the "sedition", state news agency IRNA said.

The crackdown has drawn international condemnation and sanctions against Iran from Britain, Canada and the United States.

European Union countries agreed this week to level new sanctions, and the move is due to be endorsed at the bloc's foreign ministers' meeting in Luxembourg on Monday.

Iran's supreme leader has accused the country's enemies, including the United States and Israel, of fomenting the "riots".

In response to the protests, the clerical state's security forces have also launched a campaign of mass arrests of artists, dissidents, journalists and athletes.