The jailed Russian opposition leader Alexey Navalny said he is ending a hunger strike after 24 days, following a dire warning by his doctors a day earlier.

Navalny, known as the Kremlin’s fiercest critic, declared the hunger strike at the end of March to demand that authorities allow his own doctors to treat him for severe back pain caused by two herniated discs. Since last weekend, Navalny’s allies have warned that his health was seriously deteriorating and this week thousands of people joined protests across Russia after his team warned he could be days from death.

Navalny’s doctors on Thursday published an open letter calling on him to end the hunger strike, saying his blood tests showed his kidneys were failing and he would soon fall into a likely fatal coma.

Navalny, 44, in a message posted on Instagram on Friday said he was now accepting that advice and would begin taking food again. He said he was stopping the strike in part because he said it had achieved some progress in forcing authorities to accept his demands for more medical care, noting that he had now been examined twice by non-prison doctors.

“Doctors, who I trust completely, yesterday released a statement that we had achieved enough for me to stop my hunger strike,” Navalny wrote. “And also — I’ll say it frankly — their words about how my tests show: ‘in a minimal amount of time there will be no one to treat’ … hmmm … it seemed to me they deserved attention.”

Navalny also thanked people in Russia and around the world for their “huge support,” saying it had forced authorities to soften their refusal to treat him.

Authorities on Sunday moved Navalny to a prison hospital at another nearby penal camp, where he was being given intravenous drips with glucose, according to his lawyers. This week, he was taken to a hospital close by in the city of Vladimir where he was examined by a group of non-prison doctors.

Navalny said that already amounted to a shift in his treatment, despite authorities continued refusal to let his own doctors examine him. He said he still wanted a doctor to his back pain, which is causing him to lose sensation in his arms and legs.

“Thanks to the huge support from good people around the whole country and the whole we have already made huge progress,” Navalny said in the social media post. “Two months ago, they smirked at my requests for medical help. Now a council of civilian doctors has twice examined me. They are examining me and doing tests and are giving me the results and the conclusions.”

Navalny also said he was stopping because a number of ordinary Russians have also declared their own hunger strikes in solidarity with him and he did not want to risk their health. He asked people to wish him good luck, saying the process of recovering and taking food again after 24 days would be a difficult and long one.

The dire warnings about Navalny’s health prompted concern around the world, with European countries and the United States warning Russia that it would face consequences if Navalny died in prison.

Thousands of people in dozens of Russian cities joined the protests called by Navalny’s team on Wednesday. Police detained close to 2,000 people during the demonstrations, but with the exception of in St. Petersburg, police were generally far less aggressive than at similar protests in January after Navalny was first arrested.

Russian authorities have insisted Navalny’s treatment was adequate and the Kremlin had rebuffed Western demands that he be released and be given access to proper medical care.

Navalny was arrested in January when he returned to Russia for the first time since surviving a near fatal poisoning with a nerve agent last summer. He was sentenced to two-and-a-half years in a prison camp for alleged parole violations in case widely condemned as politically motivated.

Although the end of Navalny’s strike removes the immediate threat to him, his movement is under intense pressure from authorities who are moving now to outlaw his organizations. A Moscow court will begin hearings for a case brought by prosecutors to declare Navalny’s Anti-Corruption Foundation and his regional campaign offices “extremist groups,” using legislation that is nominally intended for violent terrorist groups such as ISIS. Anyone participating in Navalny’s organizations or even publicly voicing support for them could face lengthy prison sentences.