Top Trump administration officials are meeting Ukrainian negotiators in Florida this weekend, pushing to broker an end to Russia's war in Ukraine and setting the stage for key talks planned this week in Moscow with Russian leader Vladimir Putin.

In Russia, a major oil terminal near the port of Novorossiysk stopped operations Saturday after a strike by unmanned boats damaged one of its three mooring points, according to a statement from the Caspian Pipeline Consortium, which owns the terminal.

As Washington ramps up its negotiations with Ukraine and Russia and U.S. President Donald Trump expresses optimism that a peace deal could be close, there are still some very critical and contentious issues on which Kyiv and Moscow are in deep disagreement.

Ukraine’s chief negotiator, in an exclusive interview, says conceding sovereign territory is off-limits in peace talks.

"None of us really know what Zelenskyy is like operating solo, because he never has," one expert told NBC News.

Ukrainian President Volodymyr Zelenskiy will visit French President Emmanuel Macron in Paris on Monday, Macron's office said, as the Ukrainian leader finds himself in the most difficult political and military situation since Russia's invasion in 2022.

Andriy Yermak has played a crucial role in the war with Russia and is Ukraine's lead negotiator in peace talks.