Ukrainian President Volodymyr Zelensky's chief of staff has warned that his nation is in danger of losing its war against Russia if more US military aid is not forthcoming. Andriy Yermak said 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 on Tuesday. Mr Yermak's dire assessment was given just hours before Mr Zelensky pulled out of a scheduled video conference with US senators to brief...