Russian billionaire Roman Abramovich was a victim of apparent poisoning earlier this month after attempting peace talks with Ukrainian officials, according to reports.
Mr Abramovich was allegedly targeted at a meeting in Ukraine after he accepted a Ukrainian request to help negotiate an end to the Russian invasion, the Wall Street Journal said.
At least two senior members of the Ukrainian team were also affected with all three men suffering from red eyes, constant and painful tearing, and peeling skin on their faces and hands.
It's believed the alleged poisoning was organised by Moscow hardliners who wanted to sabotage the talks in Kyiv, the publication said.
Ukrainian officials downplay poisoning claims
Ukrainian officials are said to have poured cold water on the report with Ukrainian negotiator Mykhailo Podolyak saying "there is a lot of speculation, various conspiracy theories" as to what happened.
Rustem Umerov, another member of the negotiating team, urged people not to trust "unverified information".
While Ukrainian Foreign Minister Dmytro Kuleba later suggested that "everyone is thirsty for news and sensations".
However, he also added wryly: "I advise anyone going for negotiations with Russia not to eat or drink anything, (and) preferably avoid touching surfaces".
A US official remained vague about the reason why Mr Abramovich and the negotiators fell ill, suggesting it was an "environmental" reason, and "not poisoning." He did not elaborate further, according to reports.
Mr Abramovich and the Ukrainian negotiators have since improved from the suspected poisoning which did not stop Mr Abramovich from working, Reuters confirmed.
Symptoms 'consistent with poisoning'
Bellingcat, an investigative journalism group, reported that the men had symptoms "consistent with poisoning with chemical weapons".
Citing experts, Bellingcat said the dosage and type of toxin used was not enough to be life-threatening and "most likely was intended to scare the victims as opposed to cause permanent damage".
"The victims said they were not aware of who might have had an interest in an attack," it said.
The three men reportedly only consumed water and chocolate in the hours beforehand. A fourth member of the team consumed the same but did not experience symptoms, Bellingcat said.
Mr Abramovich was hit by sanctions imposed by the West, specifically the UK resulting in him being forced to sell Chelsea FC, the Premier League soccer club he acquired in 2003.
He was one of several Russian billionaires impacted by the sanctions which also targeted Russian companies and Russian officials, in an attempt to force Putin to withdraw from Ukraine.
The Kremlin has said Mr Abramovich played an early role in peace talks between Russia and Ukraine but the process was now in the hands of the two sides’ negotiating teams, Reuters reports.
Negotiators from both Russia and Ukraine are due to meet in Istanbul on Tuesday for the first face-to-face peace talks in more than two weeks.
Mr Kuleba said Ukraine hopes to agree to a ceasefire, but his government would not hand over any land or sovereignty to Russia as part of the negotiations, he said.
Do you have a story tip? Email: firstname.lastname@example.org.