Ukrainian President Volodymyr Zelensky, currently in Ankara, has criticized Russia for sending what he called “stand-in props” to peace talks in Turkey. Zelensky had earlier said he would only attend if Russian President Vladimir Putin was present, BBC reported.

Russia confirmed that Putin will not attend and responded by calling Zelensky a “clown and a loser,” according to a statement from its foreign ministry.

Despite the tensions, talks between Russian, Ukrainian, and US delegations are set to begin this afternoon. Observers note that the Russian delegation appears to be low-level, according to BBC.

US President Donald Trump, who is on a four-day tour of the Middle East, said he may travel to Istanbul on Friday if today’s talks show progress.