Peace negotiations between Ukraine and the U.S. advance in Florida after Andriy Yermak's resignation, with Rustem Umerov now leading Ukraine's diplomatic team.

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

A new U.S. push to end Russia-Ukraine fighting has set off a flurry of diplomacy by American, European, Russian and Ukrainian officials.

Russia launched its largest barrage of drones and missiles in a month across Ukraine, killing at least three people, Ukrainian President Volodymyr Zelensky said Saturday, as a Kyiv delegation heads to the United States for fresh peace talks.

Trump's Ukraine peace talks show potential as envoy meets Russian officials, but territorial disputes remain the key obstacle to ending the ongoing war.

President Volodymyr Zelenskiy's powerful chief of staff, who headed Ukraine's negotiation team at fraught U.S.-backed peace talks, quit on Friday, hours after anti-corruption agents searched his home.