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.
Ukraine’s embassy in Washington DC did not immediately respond to a BBC question asking for further explanation for the cancellation.
It comes on the heels of a renewed push by the White House for additional support for Ukraine.
The US Congress, however, is still not close to a deal on a compromise spending package that would help fund the war effort.
“We are out of money – and nearly out of time,” wrote Shalanda Young, the White House budget director, in a letter to Republican and Democratic leaders published on Monday.
She warned that a failure by Congress to approve more military aid to Ukraine before the end of the year would “kneecap” the nation in its fight against Russia and that there was no “magic pot of funding” left to draw from.
On Monday, however, the Republican Speaker of the House of Representatives, Mike Johnson, seemed dismissive of the latest pleas to provide tens of billions of dollars more in funding. (BBC)