Sen. Mike Rounds also expressed frustration that the United States hadn’t given Ukraine more weapons to win the war.

While the incoming Trump administration appears determined to end U.S. support for Ukraine, other western allies — including Canada — say they're not ready to give in. But can they fill the vacuum if America decides to cut and run?

Tit-for-tat moves this week included the use of American-made ballistic missiles to strike inside Russia, and new nuclear threats from Moscow. Neither appear to have influenced the war on the ground.

Russia's new intermediate-range ballistic missile has NATO members on edge after the missiles were used in a strike on Ukraine early Thursday morning.