The Biden administration has sanctioned Iran’s so-called “morality police” for alleged abuses and violence against Iranian women and protesters, as Iranians have taken to the streets over the recent death of a 22-year-old woman after her detention by the police force.

The death last week of Mahsa Amini, a 22-year-old who was arrested in Tehran for “unsuitable attire”, has unleashed a wave of anger across Iran, as well as global condemnation.

On Thursday, the US Department of the Treasury sanctioned the country’s “morality police”, as well as seven leaders of Iranian security organisations that it said “routinely employ violence to suppress peaceful protesters and members of Iranian civil society, political dissidents, women’s rights activists, and members of the Iranian Baha’i community”.

“Mahsa Amini was a courageous woman whose death in Morality Police custody was yet another act of brutality by the Iranian regime’s security forces against its own people,” Treasury Secretary Janet Yellen said in a statement.

“We condemn this unconscionable act in the strongest terms and call on the Iranian government to end its violence against women and its ongoing violent crackdown on free expression and assembly.”

Earlier this week, an Iranian police official denied reports that Amini was beaten in custody.

Tehran’s police chief, Brigadier-General Hossein Rahimi, said on Monday that she was detained for wearing tight trousers and wearing her headscarf improperly, but that claims she was mistreated were “completely false”.

“Cowardly accusations have been levelled against the police, which we will defer to the day of judgement, but is it possible to shut down the society’s security?” Rahimi asked.

On Thursday, Iran’s Islamic Revolutionary Guard Corps (IRGC) also called on the judiciary to prosecute people who are circulating “false news and rumours”, in an apparent bid to take the steam out of the protests.

In a statement, the IRGC expressed sympathy for the family and relatives of Amini.

“We have requested the judiciary to identify those who spread false news and rumours on social media as well as on the street and who endanger the psychological safety of society and to deal with them decisively,” the group said.

Amini’s case has struck a chord with many across Iran, amid growing anger over civil liberties, as well as economic hardships linked to sanctions.

At least six protesters have been killed to date, according to Iranian media and officials, as well as a police officer and two members of a pro-government militia. However, activist groups say the death toll is higher.

NetBlocks also reported a “nation-scale loss of connectivity” on Iran’s main mobile telephone provider and another company’s network.

Thursday’s US sanctions will freeze the assets of the targeted individuals and entities in the United States and make it illegal for American citizens to do business with them.

Washington has been piling sanctions on Tehran since former US President Donald Trump withdrew from the Iranian nuclear deal in 2018.

The multilateral pact, formally known as the Joint Comprehensive Plan of Action (JCPOA), had seen Iran scale back its nuclear programme in exchange for a lifting of international sanctions against its economy.

But numerous rounds of indirect negotiations to restore the agreement since US President Joe Biden took office in early 2021 have stalled.

Speaking at the United Nations General Assembly on Wednesday, Biden said “while the United States is prepared for a mutual return to the Joint Comprehensive Plan of Action if Iran steps up to its obligations, the United States is clear: We will not allow Iran to acquire nuclear weapons”.

Biden also mentioned the ongoing anti-government protests in Iran, saying his administration stood “with the brave citizens and the brave women of Iran who right now are demonstrating to secure their basic rights”.