MOSCOW, Russia - Journalist Marina Ovsyannikova, who fell ill in France where she lives in exile after protesting the offensive in Ukraine on Russian state TV, said Friday that tests had not revealed poisoning.

Several Kremlin critics have reported being poisoned, and on Thursday French prosecutors opened an investigation into suspected poisoning after Ovsyannikova felt unwell.

"I'm feeling much better now," she posted on Telegram. "Most of the test results are back. There are no toxic substances in the blood. We're not talking about poisoning."

No white powder had been found, she added, contrary to what was first reported.

"The deterioration of my condition was so sudden that the French police decided to investigate," she said, posting from what appeared to be her hospital bed.

She said prosecutors opening an investigation was "not surprising, since Putin's Russia has long been associated with war and the poisoning of politicians and journalists".

Ovsyannikova, who fled Russia last autumn, had held up a protest placard during the main evening news programme on Russia's Channel One in March 2022.

In her absence, a Russian court sentenced her to more than eight years in prison this month for a separate protest she made outside the Kremlin four months later.

Several high-profile opposition politicians have said they were poisoned for political reasons, including Alexei Navalny and Vladimir Kara-Murza.

The government of Germany, where Navalny recovered, said tests provides clear proof that he was poisoned by a chemical nerve agent Novichok.

The Kremlin has repeatedly dismissed claims that it has targeted critics in this way.

But it has ramped up pressure on independent media and NGOs, with many declared foreign agents or shut down under fear of prosecution.