The Russian government on Friday designated a chart-topping rapper as a “foreign agent,”a label that has been widely seen as part of authorities’ efforts to muzzle critical voices.

Oxxxymiron, whose real name is Miron Fyodorov, was added to the justice ministry’s “foreign agent” list alongside Dmitry Glukhovsky, a veteran science-fiction writer, and Alyona Popova, a prominent feminist and one-time face of Russia’s campaign for a domestic violence law.

Oxxxymiron, a dual Russian-British national, has called the Kremlin’s invasion of Ukraine “a catastrophe,” and publicly called for the creation of an anti-war movement. He cancelled a sold-out Russian tour shortly after Moscow’s troops rolled into Ukraine on Feb. 24, and organized benefit concerts in Western Europe and Turkey, with proceeds going to Ukrainian refugees.

In August, authorities said they were investigating the rapper’s work under Russia’s anti-extremism laws, which have been expanded several times to cover a broadening spectrum of dissenting speech.

Russian law allows organizations and individuals deemed to be involved in political activity that receive funding from abroad to be declared foreign agents. The term carries a strong pejorative sense and implies additional government scrutiny.

The rapper, whose lyrics are often political, has previously attended rallies in support of jailed Kremlin foe Alexei Navalny.

Glukhovsky, the author of the 2002 post-apocalyptic novel “Metro 2033″ who is believed to be abroad, has also hit out at Russia’s war in Ukraine. He was put on a wanted list in connection with critical social media posts and columns in Western media.

In June, a Moscow court ordered his arrest in absentia on the charge of “discrediting the Russian army,” amid an unprecedented crackdown on dissenters. If convicted, he faces up to 10 years in prison.

One of Russia’s most ardent rights campaigners, Popova has fought for years to lobby Russian lawmakers to adopt legislation to protect women from domestic violence. Her social-media campaign at one point encouraged Russian women to post images of themselves with make-up resembling bloody cuts or bruises, along with the hashtag “I didn’t want to die.” The viral response prompted a surge in discussions around attitudes towards abuse survivors.

In 2021, Popova made countering domestic violence the central plank of her ultimately unsuccessful bid to join the State Duma. She has repeatedly voiced her support for women running for political office in order to address social issues in Russia.