The unrest, which poses one of the biggest challenges to theocratic rule in Iran since the 1979 Islamic Revolution, also saw groups of oil workers holding protests on Saturday to demand higher wages, according to reports on social media.

The wider unrest currently gripping Iran was triggered by the Sept. 16 death in detention of Mahsa Amini, a 22-year-old woman who was arrested for wearing "inappropriate attire" under Iran's strict Islamic dress code for women.

Authorities on Saturday detained Taraneh Alidoosti, star of "The Salesman" which won an Academy Award for best foreign language film in 2016, after she voiced support for the protests and posted a photo of herself without a head scarf with a sign reading "Woman, life, freedom" - a main slogan of demonstrators.

"Alidoosti, who did not provide documents backing up some of her claims, was arrested hours ago by an order of the judicial authority," the official news agency IRNA quoted a judiciary statement as saying.

The statement said several celebrities had been summoned over "unsubstantiated comments about recent events, and publishing provocative material in support of earlier street riots", and that some were detained. It did not elaborate.

In 2020, Alidoosti received a five-month suspended sentence after she criticised on Twitter the morality police, which enforces hijab or Islamic dress code.

Alidoosti was the latest of dozens of artists, journalists and lawyers detained over the past three months for speaking out against a violent security crackdown on the protesters, some of whom have been released on bail.

Separately, Central Bank governor Ali Salehabadi acknowledged that "the events of the past two months" had contributed, along with U.S. sanctions, to a record fall of the Iranian currency, but suggested dollars could be injected into the market to shore up the troubled rial.

"To make adjustments in the (foreign exchange) market, we in the Central Bank will act both as a market-maker and as a hard currency policymaker," Salehabadi told state TV. "Whichever hard currency is more in demand, we will offer that in the market."

Iran's troubled currency fell to a new low against the U.S. dollar on Saturday as Iranians desperate to find safe havens for their savings have been trying to buy dollars, other hard currencies or gold.

The dollar sold for as much as 395,600 rials on the unofficial market, up from 386,800 on Friday, according to foreign exchange site Bonbast.com.

The economic daily Donya-e-Eqtesad’s website gave the dollar rate as 382,300, up 1.2% from Friday.

The rial has lost nearly 20% of its value since the nationwide protests erupted three months ago. In May 2018, the currency was trading at about 65,000 per U.S. dollar just before the United States withdrew from Iran's nuclear deal with world powers and reimposed sanctions on the country.

A video shared on Twitter by 1500tasvir, an account that has 400,000 followers, showed what it said was a metro station in Tehran on Saturday with the crowd chanting, "Political prisoners must be freed!"

According to the activist HRANA news agency, 495 protesters had been killed as of Friday, including 68 minors. Sixty-two members of the security forces have also been killed. It said 18,450 people are estimated to have been arrested.