ISTANBUL—A few weeks ago, Roman Abramovich was the world’s best-known Russian oligarch, moving to sell or transfer some of his trophy assets, like English soccer powerhouse Chelsea FC, amid an array of Western sanctions following Russia’s invasion of Ukraine.

On Tuesday, he was playing a different public role: peace negotiator. Ukrainian officials say the Russian billionaire has been filling a key, if unofficial, role as a backchannel to Moscow in peace talks that have been conducted in fits and starts for weeks. Ukrainian negotiator David Arakhamia, the majority leader in the country’s parliament, said that Mr. Abramovich had been included in the formal negotiations in Istanbul because his role as an unofficial go-between had now been widely reported by the media.

To Read the Full Story