Ukrainian President Volodymyr Zelensky has called off a high-profile briefing with US lawmakers amid an impasse over future US funding for the country.
Virtual appearances in the Senate and House had been scheduled for Tuesday, but were cancelled at the last moment.
It came after a top Ukrainian official warned they are in danger of losing the war against Russia if more US military aid is not approved.
Senate leader Chuck Schumer did not explain why Mr Zelensky was a no-show.
The chamber’s top Democrat said the Ukrainian president was occupied with a “last-minute” matter, without providing further detail.
The Ukrainian leader was due to appear by video at a classified briefing of senators by top US officials. The meeting proceeded but discussions about the aid package soon descended into chaos.
Mr Zelensky’s chief of staff, Andriy Yermak, said earlier on Tuesday there was a “big risk” of Ukrainian defeat without continued US support.
“It will be difficult to keep in [the] same positions and for the people to really survive,” he added, in a speech at the US Institute of Peace in Washington DC.
Mr Yermak’s dire assessment was given just hours before Mr Zelensky pulled out.
Read more at BBC.com