POKROV (Russia), April 6 — Russian police stepped up security at the prison holding Kremlin critic Alexei Navalny today as his supporters prepared to stage a protest outside the facility to demand that authorities give him proper medical care.

Navalny, 44, a prominent opponent of President Vladimir Putin, announced a hunger strike last week in protest at what he said was the refusal of prison authorities to treat him properly for acute back and leg pain.

A group of his allies said they would protest at the prison in the town of Pokrov 100 km (60 miles) east of Moscow from Tuesday unless he saw a doctor of his choice and was given what they regarded as proper medicine.

Prison authorities say his condition is satisfactory and he has been provided with all necessary medical care.

Late on Monday, his allies said the protest would go ahead after Navalny said he was continuing his hunger strike, although he had a high temperature and bad cough and three inmates in his ward had been hospitalised with tuberculosis.

The pro-Kremlin Izvestia newspaper later cited the state prison service saying that Navalny had been moved to a sick bay and tested for the coronavirus.

This morning, police officers, one with a police dog, set up a makeshift checkpoint in front of the prison gate and used a metal barrier to block the road 100 metres from it.

They closed the parking lot to all but prison staff, and checked the IDs of reporters and prison workers.

"It is now under a special (security) regime,” a police woman told Reuters.

Antonina Romanova, a Navalny supporter, said she had come to show solidarity.

"I believe he is innocent. I’m fully on his side,” she said. "It happens that for some reason the people who can sort things out in the country end up in jail,” she said. — Reuters