Russian state prosecutors said they would ask a court on Tuesday to jail opposition politician Alexei Navalny for up to three and a half years, and the Kremlin said it would not listen to US complaints about his case.

Riot police detained more than 5 300 people who took part in protests across Russia on Sunday calling for the release of Navalny, a prominent critic of President Vladimir Putin who was detained last month on his return from Germany.

The political unrest is a headache for Putin, 68, who has dominated Russian politics for over two decades. The case has set off new talk of Western sanctions on Russia and raised tension as US President Joe Biden launches his administration.

Sunday’s rallies prompted US Secretary of State Antony Blinken to condemn what he said was the persistent use of harsh tactics against peaceful protesters and journalists, and to call for Navalny’s release.

The Kremlin said Moscow would ignore Blinken’s comments about what it said were illegal protests inside Russia and warned against Washington imposing any new sanctions.

“…We are not prepared to accept or heed American statements about this,” Kremlin spokesman Dmitry Peskov said.

A court on Tuesday is set to consider a request from Moscow’s prison service to hand Navalny a jail term of up to three and a half years for alleged parole violations which he calls trumped up.

The Prosecutor General’s office said on Monday that the request was legal and justified, and that state prosecutors would ask a court to grant the prison service’s request.

KREMLIN HITS BACK

Navalny, 44, is serving a 30-day stint in jail after being immediately arrested upon arrival back in Russia after having treatment in Germany following a nerve agent attack in Russia.

He says Putin ordered the attack, something the Kremlin denies.

Navalny ally Vladimir Ashurkov published a letter addressed to Biden on Saturday appealing for sanctions against businessmen and officials identified as being close Putin allies.

The Kremlin hit back on Monday, saying the move showed Navalny’s Anti-corruption Foundation was acting as a “foreign agent”, a designation formally given to the group in 2019 under a law that civil society workers in Russia say is often used to harass critics.

Peskov, the Kremlin spokesman, also said a large number of “hooligans and provocateurs” had been present at Sunday’s nationwide rallies and accused them of acting aggressively towards the police.

“There can be no conversation with hooligans and provocateurs, the law should be applied with the utmost severity,” Peskov told reporters.

Pavel Chikov, a lawyer and rights advocate, said police had opened 40 criminal cases in 18 different regions related to the two weekends of protests. The OVD-Info protest monitor said at least 82 journalists were detained at Sunday’s rally.

Navalny’s allies have called on supporters to gather outside the Moscow court on Tuesday during his hearing.

A court placed his spokeswoman, Kira Yarmysh, under house arrest until March on suspicion of breaching COVID-19 regulations at unsanctioned rallies on January 23. Several others, including Navalny’s brother Oleg, are already under house arrest.