Ukrainian President Zelensky has scrambled to re-engage Washington following the Oval Office debacle -- declaring himself ready to work towards a peace deal under the US president's "strong leadership" and to finalise an accord on American access to Ukrainian mineral resources.

"I welcome very much that the United States and Ukraine, as we speak, are discussing how to go forward with this, and how to solve some of the difficulties," Rutte told reporters at NATO headquarters.

"I'm cautiously optimistic that this will lead to good results," he said, voicing confidence that "things can move forward in a positive sense" following Zelensky's outreach in a tweet and follow-up letter to Trump -- which the US president acknowledged in his address to Congress Tuesday.

The White House blow-up saw Trump brand Zelensky as ungrateful and led Washington to cut the military aid and intelligence sharing that has helped Kyiv fight off Russia's invasion for the past three years.

The moves have cemented fears in Kyiv and Europe that Ukraine could be forced to accept a peace settlement on terms favourable to Moscow or risk losing US support entirely.