They “have to understand (that) only in unity we can win (against) Russia,” he said.

Asked whether it would be a good idea to invite former US president and 2024 presidential hopeful Donald Trump to Kyiv, Mr Zelensky replied: “I invited publicly, but it depends on his wishes.”

“If … he will come, I’m ready even to go with him to the front line,” he added.

Speaking separately at the same conference, NATO secretary-general Jens Stoltenberg said Congress’ delay has meant the flow of US weapons and ammunition dropped, with a direct impact on the front line.

“Every week we wait means that there will be more people killed on the front line in Ukraine,” he said.

Estonian prime minister Kaja Kallas, whose country directly borders Russia, pointed to the history of the 1930s.

“If America isolates itself, it eventually is going cost you more,” she said, warning that if “aggression pays off somewhere, it serves as an invitation to use it elsewhere, jeopardizing global security.”

Mr Zelensky argued that “among us, there is no one for whom the ongoing war in Europe does not pose a threat”.

“Please do not ask Ukraine when the war will end,” he said. “Ask yourself why is Putin still able to continue it.”