At least two members of Ukraine's negotiating team and Russian oligarch Roman Abramovich suffered symptoms of poisoning following talks between Russian and Ukrainian delegations on March 3, The Wall Street Journal reported on Monday.
The report, which was confirmed by the investigative journalistic group Bellingcat, said the symptoms included skin and eye irritation. However, these all appeared to subside within a day.
The condition of those who reported suffering the effects of supposed poisoning have all improved and none is in danger, The Wall Street Journal reported.
Suspected chemical poisoning
The reported poisoning took place during talks held in Ukraine. According to Bellingcat, the Ukrainian negotiators first felt the symptoms that night after returning to Kyiv.
These included "eye and skin inflammation and piercing pain in the eyes," the group wrote on Twitter.
The negotiators reached out to Bellingcat, which connected them with a chemical weapons specialist for examination.
"The experts concluded that the symptoms were most likely the result of international poisoning with an undefined chemical weapon," the investigative group wrote.
Abramovich the mediator
Abramovich was involved in early talks, the Kremlin confirmed, but later rounds had been taken over by Russian negotiators.
The billionaire and current owner of Chelsea Football Club had been traveling between Moscow and Lviv in an attempt to mediate between the two sides.
Ukrainian President Volodymyr Zelenskyy said the oligarch had wanted to "do something" to "help somehow" with the aim of de-escalation. Abramovich also has long-standing ties to Russian President Vladimir Putin.
Abramovich was also the subject of personal sanctions following Russia's invasion of Ukraine. He has said that he will sell Chelsea.
While it is not clear who was behind the suspected poisoning, it has been frequent tactic used against opponents of the Kremlin.
Opposition figure Alexei Navalny was poisoned with Soviet-era agent Novichok while on a domestic flight and had to be taken to Berlin for treatment.
Warnings against 'speculation'
Ukrainian negotiator and presidential advisor Mykhailo Podolyak warned against false information following the reports of alleged poisoning.
"In the information sphere right now there is a lot of speculation, different conspiracy theories and elements of one information game or another," Podolyak said, according to local media.
Rustem Umerov, a member of the delegation who was said to have been one of the victims, wrote on social media on Monday morning that he was feeling "fine."
"This is my response to all the yellow news 'gossip' spreading around. Please do not trust any unverified information. We have an informational war ongoing as well," he said.