Ukrainian President Volodymyr Zelensky offered Wednesday to swap pro-Kremlin tycoon Viktor Medvedchuk, who was arrested by Kyiv after escaping house arrest, for Ukrainians captured by Russia.
Medvedchuk, 67, counts Russian President Vladimir Putin among his personal friends and says the Kremlin leader is godfather to his youngest daughter Darya.
"I propose to the Russian Federation to exchange this guy of yours for our boys and our girls who are now in Russian captivity," Zelensky said in a video address posted on Telegram.
"And may Medvedchuk be an example for you. Even the former oligarch did not escape. What can we say about much simpler criminals from the Russian hinterland? We will get everyone."
Ukrainian authorities announced Tuesday they had captured a prominent pro-Kremlin tycoon who escaped from house arrest after Russia's invasion.
Zelensky posted a picture online of a disheveled-looking Medvedchuk with his hands in cuffs and dressed in a Ukrainian army uniform.
"A special operation was carried out by the Security Service of Ukraine. Well done!" Zelensky wrote on Telegram.
Security agency chief Ivan Bakanov said agents had carried out a "lightning-fast and dangerous multi-level special operation to detain" the Russia-friendly lawmaker.
Medvedchuk, one of the richest people in Ukraine, is a hugely controversial figure for his close ties to Moscow.
He was being held under house arrest since last year on treason charges over accusations of attempting to steal natural resources from Russia-annexed Crimea and of handing Ukrainian military secrets to Moscow.