Moscow court extended house arrest of four prominent activists and supporters of jailed Kremlin critic Alexei Navalny until summer, police surveillance of Mediazona and OVD-Info websites reported Thursday.

Ten Navalny supporters are accused of “inciting massive violations” of coronavirus restrictions by calling on supporters across the country to protest his imprisonment in late January and early February. Critics accused the Kremlin of locking up Navalny’s closest allies to quell dissent ahead of the September parliamentary elections.

The Basmanny District Court in Moscow has decided to keep Navalny spokesperson Kira Yarmysh and Pussy Riot activist Maria Alyokhina under house arrest, as well as Navalny Moscow office head Oleg Stepanov and municipal deputy Dmitri Baranovsky until June 23.

The court is supposed to to deploy themselves six more supporters under house arrest later in the day, according to BBC Russia.

They include another member of Pussy Riot and municipal deputy Lucy Shtein and the lawyer of the Anti-Corruption Foundation Lyubov Sobol as well as the brother of Navalny Oleg, the ophthalmologist and leader of the union of independent doctors Anastasia Vasilyeva, the senior associate Nikolai Lyaskin and municipal deputy Konstantin Yankauskas.

All 10 face up to 2 years in prison for the coronavirus-related charges that Russian lawmakers passed at the start of the epidemic last spring.

The court issued its decision two days after Hollywood stars such as Whoopi Goldberg, Martin Sheen and Gillian Anderson signed a letter of solidarity with Alyokhina and Shtein.

Navalny was sentenced to two and a half years in a penal colony last month for violating parole while recovering overseas from a poisoning attack last year. The United States and the European Union have imposed sanctions on Russian officials and state entities for the poisoning of Navalny, which the Kremlin denies, as well as his imprisonment.