Jailed Russian opposition politician Aleksei Navalny has been transferred to a prison with harsher conditions.

Navalny wrote on Telegram on June 15 that he had been transferred a day earlier to the Correctional Colony No. 6 in the town of Melekhovo, where he is currently in quarantine.

Navalny's statement came after his spokeswoman said that he was currently in the penitentiary in Melekhovo.

"Aleksei Navalny is now in quarantine in the Correctional Colony No. 6 in Melekhovo. His lawyer managed to see him. Aleksei says hi to everyone," Kira Yarmysh wrote on Twitter.

The day before, Yarmysh and other associates of the outspoken Kremlin critic expressed concerns about his whereabouts after the prison where he was held for months told his lawyer that he was no longer there.

Navalny was expected to be transferred to a prison with harsher conditions after a Moscow court rejected his appeal in May against a new nine-year jail term he was handed in March on embezzlement and contempt charges.

He was already serving a prison term from an earlier case in the prison in Pokrov, some 200 kilometers east of Moscow.

The outspoken foe of Russian President Vladimir Putin and his supporters have rejected all charges against him, calling them politically motivated.

Amid concerns about Navalny's whereabouts, journalists asked Kremlin spokesman Dmitry Peskov on June 15 about Navalny, and Peskov answered that the "Kremlin does not follow inmates' transfers."

Navalny previously said that he might be transferred to Correctional Colony No. 6 in Melekhovo, where inmates were reported to have been tortured. Melekhovo is about 150 kilometers east of the Pokrov prison where he had been serving his first sentence.

Both towns are in the Vladimir region, east of Moscow.

Olga Romanova, a noted activist involved in defending inmates' rights, told Current Time that in the prison in Melekhovo, Navalny will be allowed fewer family visits and fewer letters and parcels.

The United States on June 14 called on Russia to grant Navalny access to his lawyers and medical care and condemned the "politically motivated" actions against him.

Russian authorities "will be held accountable by the international community for anything to befall Mr. Navalny," State Department spokesman Ned Price said.

"We reiterate our call for his immediate release as well as an end to the persecution of his many supporters," Price said.

Navalny, 46, was arrested in January 2021 upon his arrival to Moscow from Germany, where he had been treated for a poison attack with what European labs defined as a Soviet-style nerve agent.

He was then handed a 2 1/2-year prison sentence for violating the terms of an earlier parole because of his convalescence abroad. The original conviction is widely regarded as a trumped-up, politically motivated case.

Navalny has blamed Putin for his poisoning. The Kremlin has denied any role in the attack.

International organizations consider Navalny a political prisoner. The European Union, U.S. President Joe Biden, and other international officials have demanded Russian authorities release him.

With reporting by Current Time