Russian opposition leader and Kremlin critic Alexei Navalny on Monday claimed to have tricked a security agent into admitting that the Federal Security Service (FSB), Russia’s intelligence agency, orchestrated his poisoning earlier this year. 

In a blog post, Navalny said that the FSB had placed poison in his underwear, adding he got the information from a man named Konstantin Kudryavtsev, who he claimed to be a chemical weapons expert with the FSB, AFP reported.

Also Read | Alexei Navalny would be dead had Russia poisoned him, says Vladimir Putin

“I called my killer. He confessed everything,” Navalny said in a tweet. 

Navalny said he disguised his phone number and told Kudryavtsev he was an aide to Security Council chief Nikolai Patrushev, asking for information on the attempted poisoning for an official report. 

He did not give any proof for his claims, but said that a voice analysis will confirm “that it is indeed” Kudryavtsev. 

He also published an audio recording and a transcript of the phone call, along with a video of him conducting the conversation. 

In the audio recording, the voice initially sounds hesitant and cautious but eventually justifies why Navalny managed to survive.

There were no immediate reactions from Russian authorities.

Also Read | Russian police rule out Alexei Navalny poisoning, diagnose pancreatitis

Navalny, 44, fell violently ill during a flight from Siberia to Moscow in August and was hospitalised in the Russian city of Omsk before being transported to Berlin by medical aircraft.

A joint media report led by the Bellingcat investigative website last week revealed what it said were the names and photos of chemical weapons experts from the FSB that had tailed Navalny for years.

President Vladimir Putin last week rejected the report, saying if Russia’s security services were behind Navalny’s poisoning he would be dead.

In his blog post on Monday, Navalny said that last week he called the security agents identified in the report. He said nearly all hung up on him except the man he said was Kudryavtsev.

During their call, Kudryavtsev said his unit had not expected the pilot to make an emergency landing in Omsk.

He said that if the flight had been allowed to continue, Navalny would not have survived.

The agent said the attacker had placed the poison in the inside of one of Navalny’s underpants.

He also detailed how he and another FSB agent flew to Omsk to take care of Navalny’s clothing and removed any trace of the poison.

However, Kudryavtsev never explained his exact role in the operation.

Der Spiegel as well as Bellingcat and Russian website The Insider were given access to Navalny’s account and published reports on Monday too.