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

Trump will meet Putin in Alaska to negotiate a ceasefire in Ukraine. But Zelensky has objected to being left out.

"Undoubtedly, a number of countries interested in continuing the conflict will make titanic efforts to disrupt the planned meeting between President Putin and President Trump," he said in a post in his Telegram account, specifying that by efforts he meant "provocations and disinformation".