"Though that may not be enough to compel Putin to seek peace, it does suggest that the walls are closing in on him."

Kyiv has repeatedly rejected any so-called "land swap" which would be against the Ukrainian Constitution. Zelensky's comments on Saturday acknowledge Trump's role in any peace deal with the summit but again reject the chances that Ukrainian land can be traded for peace.

The Kremlin says a meeting between Russian President Vladimir Putin and U.S. President Donald Trump has been agreed.