(CNN) Ukrainian President Volodymyr Zelensky delivered a historic speech from the United States Capitol Wednesday night, expressing gratitude for American support in fighting Russian aggression since the war began -- and asking for more.But alongside Zelensky's gratitude was a plea, emphasizing that his armed forces are outnumbered and outgunned by the Russian military even as they fight on.At one point, Zelensky drew laughs from the chamber when he said, "We have artillery, yes.Just like "brave American soldiers which held their lines" and fought against Adolf Hitler's Nazi Germany in 1944, Ukrainian soldiers "are doing the same to Putin's forces this Christmas," Zelensky said.Biden said Zelensky has shown his "strong stand against aggression in the face of the imperial appetites of autocrats," and said the US was standing alongside Ukraine in maintaining "core principles of sovereignty and territorial integrity.""