Russia-Ukraine updates: US sanctions Russian military shipbuilder, diamond miner

Russian oligarch Roman Abramovich is taking part in Tuesday's in-person negotiations between Russian and Ukrainian delegations in Turkey's capital, a Turkish presidential source told ABC News.

Abramovich is the owner of the English professional football club Chelsea. The U.K. government has included him among the wealthy Russians targeted in recent sanctions.

The Wall Street Journal reported Monday, citing unnamed sources familiar with the matter, that Abramovich and two Ukrainian negotiators suffered symptoms of suspected poisoning after peace talks in Kyiv in early March.

A Turkish presidential source told ABC News that Abramovich suspected he was poisoned after experiencing eye problems.

Turkish officials confirmed there is a discussion regarding the food protocols during Tuesday's negotiations in Istanbul.

Ukraine is warning its delegation against eating or drinking while attending in-person peace talks with Russian negotiators, amid fears of potential poisoning.

"I advise to everyone who's going to any negotiations with Russia, not to eat or drink anything, and also not to touch any surfaces," Ukrainian Foreign Minister Dmytro Kuleba said in a statement Tuesday.

The warning came a day after The Wall Street Journal reported, , citing unnamed sources, that Russian oligarch Roman Abramovich and two Ukrainian negotiators had suffered symptoms of suspected poisoning following peace talks in Kyiv in early March.

-ABC News' Julia Drozd

The latest round of in-person peace negotiations between Russian and Ukrainian delegations kicked off in Istanbul on Tuesday morning, with Turkish President Recep Tayyip Erdogan in attendance.

Erdogan addressed both sides with a brief speech before the talks began.

"Establishing a cease-fire and peace as soon as possible will be to everyone's benefit. We think that we've entered a period where we need to achieve concrete results from negotiations," Erdogan said. "As members of the delegations, you've taken on a historic responsibility. The whole world is awaiting the good news that will come from you."

Footage showing the start of the meeting was broadcast by Russian state-backed television channel RT.

Tuesday's negotiations are taking place in Dolmabahce Palace in the Besiktas district of Turkey's capital, according to Turkish state-run news agency Anadolu Agency. It's the first face-to-face talks to take place between Russia and Ukraine in more than two weeks.

Ukraine President Volodymyr Zelenskyy said during his evening address Monday that Irpin was liberated and Russian forces have been "pushed away from Kyiv."

"The occupiers are pushed away from Irpin. Pushed away from Kyiv," he said.

However, he said Russian troops still control the north of Kyiv.

"They are trying to restore the destroyed units. The level of their losses, even at 90%, is not an argument for them to stop. Hundreds and hundreds of units of burned and abandoned enemy equipment do not convince them that this will happen to everyone," he said.

Zelenskyy also said the situation in the Chernihiv, Sumy, Kharkiv regions, along with Donbas and southern Ukraine, remains tense.

"This is a ruthless war against our nation, against our people, against our children.
As of today, 143 children are known to have died," Zelenskyy said Monday.

-ABC News' Christine Theodorou