If a peace deal between Russia and Ukraine ever comes together, the U.S. could take the lead role in monitoring a large buffer zone inside Ukraine.

Ukrainian President Volodymyr Zelenskiy said on Friday thousands of foreign troops could be deployed to his country under post-war security guarantees, but Russian leader Vladimir Putin said Moscow would regard them as legitimate targets to attack.

President Vladimir Putin has said Russia will achieve all its objectives by force if Ukraine does not agree to a deal. "It seems to me that if common sense prevails, it will be possible to agree on an acceptable solution to end this conflict," Putin said. "If not, then we will have to resolve all our tasks militarily."

The main Russian nighttime targets were civilian infrastructure, especially energy facilities, Ukrainian President Volodymyr Zelensky said, as another winter approaches three years after Russia’s all-out invasion of its neighbor.

Russia rejected the notion of Western security guarantees for Ukraine on Friday, after more than two dozen countries pledged to join a "reassurance" force to deploy in the wartorn country

A source at the Élysée Palace said there were three aims behind the security guarantees: to strengthen Ukraine's armed forces; to support them by deploying a separate force to make it clear to Russia that Ukraine had Western backing;