Speaking at the Pentagon with Ukrainian Foreign Minister Dmytro Kuleba, Austin said the United States will continue to work closely with Kyiv and allies "in trying to find a way to avoid further conflict."

He praised Ukraine's "measured response" in calling for a peaceful solution "in the face of Russia's aggression, provocations and false accusations."

Russian President Vladimir Putin "can still avoid a full blown, tragic war of choice," Austin added.

Kuleba, in Washington for meetings with top officials as the crisis continued to deteriorate, said he was on a diplomatic mission.

"But these days diplomacy means also defense," he said, as Kyiv seeks broder military support from the United States.

"My message is simple: Strong Ukraine is the best deterrence of Russia," he said.