MOSCOW: Jailed Kremlin critic Alexei Navalny said Wednesday that he was being refused access to hospital treatment by prison officials after falling sick, in what his team called an underhanded attempt to kill him.

Navalny, the most prominent opponent of Russian President Vladimir Putin, said he had flu symptoms including a fever but was being kept in a punishment cell at his maximum-security prison outside Moscow.

He also requested during a court hearing on Wednesday that it be postponed because of his illness.

“I am not being hospitalised even though I requested this,” Navalny was quoted by his team as saying during the hearing, adding that prison officials had also refused to provide basic drugs.

Navalny’s spokeswoman, Kira Yarmysh, told AFP that judges had granted the postponement.

For the past two years, the 46-year-old has been held outside Vladimir, a town around 230 kilometres (145 miles) east of Moscow, after an embezzlement conviction, one of several rulings Navalny has denounced as an attempt to silence him.

A lawyer by training, Navalny has filed several lawsuits against penitentiary officials, claiming they have infringed his constitutional rights.

Earlier this week, Navalny said he was sharing his cell with a flu-stricken man, accusing officials of using the fellow inmate as a “biological weapon” to infect him.

Authorities have also placed a “mentally unwell person” in a nearby cell who has been “howling at night”, Navalny said.

His wife Yulia Navalnaya accused staff at the IK-6 prison of “torturing” him.

“Are you human?” she said in a post on Instagram.

Navalny’s team claimed that the Kremlin wanted Navalny to die in prison.

“Putin is still trying to kill Navalny but in a quieter and slower manner compared to the Novichok poisoning,” the team said on the Telegram messaging app.

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Navalny was poisoned with Novichok, a Soviet-made nerve agent, on a trip to Siberia in 2020. He barely survived, and accused Putin of being behind the attack.

In an open letter, hundreds of Russian doctors urged the authorities to stop “tormenting” Navalny and provide him with adequate care.

“The refusal of representatives of the Federal Penitentiary Service to hand Alexei the necessary medicines creates a direct threat to the life of Russian citizen Alexei Navalny,” the letter said.

US State Department Spokesperson Ned Price tweeted on Wednesday: “We echo the concerns of more than 170 Russian doctors who are calling for an end to the mistreatment of Navalny and for provision of all appropriate medical care.”