Jailed Russian opposition leader Alexei Navalny, who was recently transferred to a remote colony above the Artic circle, said Tuesday he had been put in solitary confinement.

Navalny's allies say the Kremlin is seeking to further isolate the top politician ahead of elections that are expected to easily hand Russian President Vladimir Putin a fifth term in power.

"I got seven days in SHIZO," Navalny said, referring to the Russian prison punishment cell.

Navalny regularly complains of harassment by prison authorities who regularly send him to solitary confinement over minor alleged infractions to prison rules.

This time, guards said he "refused to introduce himself according to the format, did not respond to the educational work."

This is Navalny's 24th time in the punishment cell -- SHIZO in Russian -- where he has spent 273 days according to allies. 

"The idea that Putin is satisfied with the fact that he put me in a hut in the far north and that I am no longer being tortured in SHIZO was not only cowardly but also naive," he added.

Navalny galvanised huge nationwide protests in Russia before he was jailed in 2021 on fraud charges after returning from Germany, where he was recovering from a poisoning that he blamed on the authorities.

He saw his sentence extended to 19 years on charges of extremism in 2023.

Navalny arrived in late December at the IK-3 penal colony built in the 1960s on the site of a former Gulag camp. 

In his usual dark-humour tone, he said the temperature on his prison yard walks had "never been colder" than -32 degrees Celsius (-25 degrees Fahrenheit) and joked:

"What a wonderful fresh breeze that blows into the courtyard despite the concrete fence!"

Officials and NGOs in Western countries regularly express their concerns about his detention conditions.