Ukraine’s President Volodymyr Zelensky raised the stakes ahead of a potential meeting with Vladimir Putin in Turkey on Thursday by saying he wouldn’t hold talks with any Russian representative other than the president himself.

Russian officials have already been preparing for Putin to reject the meeting, with Moscow claiming a sit-down with Zelensky would only amount to “pure spectacle.”

Russia has not yet said who it will send to Istanbul on Thursday and has refused to respond to ultimatums.