U.S. President Joseph Biden in a telephone conversation assured Ukrainian President Volodymyr Zelensky that the United States is committed to the principle of "no decisions or discussions about Ukraine without Ukraine," the White House said.

"He reaffirmed the United States' unwavering commitment to Ukraine's sovereignty and territorial integrity. President Biden made clear that the United States and its allies and partners are committed to the principle of 'no decisions or discussions about Ukraine without Ukraine,'" a press release posted on the White House website on Thursday says.

The leaders called on Russia to de-escalate tensions and agreed that diplomacy is the best way to make meaningful progress on conflict resolution.

"President Biden underscored the readiness of the United States to engage in support of confidence-building measures to advance the implementation of the Minsk Agreements, in support of the Normandy Format," it says.