Russia branded Ukrainian President Volodymyr Zelensky a 'loser' and a 'clown' as the two warring nations prepared to enter direct peace talks for the first time since 2022.
Zelensky had slammed Moscow for sending a 'dummy' delegation to Turkey as he questioned whether 'they are capable of making any decisions themselves'.
The comments from both sides could undermine the chances of a breakthrough at the landmark talks.
Russian President Vladimir Putin will not be attending, despite days of international pressure.
US President Donald Trump will only join the talks if he sees meaningful progress, but said he did not expect any advancements until he meets Putin.
