The top U.S. official for Ukraine negotiations doubled down on recent assurances from the State Department and White House that President Donald Trump did not reach any agreements on Ukraine during last week's two-hour private meeting with his Russian counterpart in Helsinki, Finland.

Russian President Vladimir Putin last week told a gathering of diplomats in Moscow that he and Trump discussed the possibility of an internationally supervised referendum in pro-Russian separatist regions of eastern Ukraine, a claim later reiterated by the Kremlin's ambassador to the U.S, according to Voice of America.

In an exclusive interview with VOA's Ukrainian service, Kurt Volker, U.S. special representative for Ukraine negotiations, said that Kremlin remarks about the referendum were not only misleading but also blatantly implausible.

"There was no move toward recognition of Russia's claimed annexation of Crimea. No support for a referendum. No movement toward Russia's position on a protection force for [Organization for Security and Cooperation in Europe] monitors that would effectively divide the country," said Volker, referring to Russia's controversial September 2017 UN proposal.

Because referendums aren't part of the 2015 Minsk agreement, which aims to end the conflict, secure a cease-fire and pave the way for regional elections, Volker said any direct vote on secession from Kyiv would lack the necessary legal framework.

"So, a lot of things that people were worried about or had predicted might happen [in Helsinki] did not happen. So, I don't think there's really any basis to be worried here," he said, noting that the administration has continued to maintain sanctions on Russia in concert with European allies and approved weapons sales to Kyiv.

The Pentagon, he added, recently unveiled plans for a new military financing package for the occupied Eastern European country.

"Let me just say this — that on all of the issues that Ukrainians would care about, nothing was given away," he said. "No handing over of gifts to Russia at Ukraine's expense."

Volker's comments supplemented initial reactions by Garrett Marquis, U.S. National Security Council spokesman, who said the White House was "not considering" supporting a referendum in eastern Ukraine, and a statement by U.S. State Department spokeswoman Heather Nauert, who said an eastern Ukraine referendum "would have no legitimacy."

The comments by the trio of U.S. officials followed days of speculation about what was discussed at the rare one-on-one meeting between the U.S. and Russian leaders with only their translators present.

Trump has been on the defensive over the summit since returning from Helsinki, especially during a key moment when he was asked about Russian meddling in the 2016 U.S. presidential election as Putin stood beside him.