MOSCOW (REUTERS) - The wife of jailed Kremlin critic Alexei Navalny stayed with him in a Russian prison for three days, taking him borsch and cherries and sending "a big Hi to everyone" on his behalf, she said in a post on Thursday (Aug 5).

Navalny is serving two and a half years in jail for parole violations in an embezzlement case he says was trumped up.

Navalny's allies accuse the authorities of using the law to crush dissenting voices ahead of September's parliamentary elections.

In an Instagram post, Yulia Navalnaya said she brought in everything her husband had told her he was missing and described preparations for the meeting.

"The guards carefully inspect the borsch for a phone inside, cut a random patty for heroin and sniff all drinks for alcohol, then undress you and search," Yulia said.

She described family meeting facilities at the prison, in the town of Pokrov about 100km east of Moscow, as having "a very decent look of a two-star hotel", with a couple of rooms and a kitchen with paintings on the walls.

The couple spent "three happy days" without glass walls or bars, according to the post which came with a picture of Yulia posing outside the prison. Navalny, described as very skinny but sun-tanned and smiling, was then taken back to his cell.

Prisoners in Russian jails have some rights for family visits, but it is up to prison authorities whether to grant permission for specific requests.

Prison authorities in the Vladimir region where Navalny's prison is located did not immediately reply to a request for a comment.

Navalny spent nearly a month on hunger strike earlier this year demanding better medical care for leg and back pain.

Last week, Russian authorities blocked access to Navalny's website along with the websites inside Russia of 48 other individuals and organisations affiliated with him, in the latest chapter in a long-running crackdown on President Vladimir Putin's most prominent domestic opponent.