Delegation members attending peace talks between Ukraine and Russia suffered symptoms of suspected poisoning after a meeting in Kyiv earlier this month, according to a report in The Wall Street Journal.

Russian billionaire Roman Abramovich and at least two senior members of the Ukrainian team, including Crimean Tatar lawmaker Rustem Umerov, were affected, according to the paper, which cited people familiar with the matter.

It said the delegation members showed symptoms that included red eyes, constant and painful tearing, and peeling skin on their faces and hands. Those affected have since improved their health, and their lives are not in danger, according to the report.

Investigators for the open-source collective Bellingcat were also involved in sourcing the Journal’s report.

Bellingcat said its sources have confirmed the events, and cited experts who investigated the matter and concluded that “poisoning with an undefined chemical weapon” was the most likely cause.

The experts said the choice of toxin and dose indicates it “most likely was intended to scare the victims, as opposed to cause permanent damage.”

The Wall Street Journal said it was not clear who was behind the suspected poisoning but said those targeted blamed hard-liners in Moscow seeking to disrupt the negotiations.

Asked Monday about the report, Ukrainian negotiator Mykhailo Podolyak said, “There is a lot of speculation, various conspiracy theories,” according to Reuters.

Reuters reported that Umerov, who was cited as one of the targets of the suspected poisoning in the Journal report, urged people not to trust “unverified information.”

The Kremlin has not commented on the report.

Abramovich is a billionaire Russian businessman with close ties to Russian President Vladimir Putin and is one of numerous oligarchs under sanctions from Western countries.

Last week, the Journal reported that Ukrainian President Volodymyr Zelenskyy asked U.S. President Joe Biden not to include Abramovich in Western sanctions, arguing that the Russian could help to negotiate a peace deal.

Some information in this report came from Reuters and Agence France-Presse.