Ukrainian President Volodymyr Zelensky met face-to-face with Donald Trump Friday with public tensions rising between the two over Ukraine's defence against Russia's invasion.

“I think we have a common view that the war in Ukraine has to be stopped and Putin can't win,” Zelensky said, referring to Russian President Vladimir Putin.

After arriving together at a conference room on Friday, Trump said “the fact that we're even together today is a very good sign”.

The meeting came at a critical time in the Russia-Ukraine war as Election Day nears in the US. Trump and Vice-President Kamala Harris, his Democratic opponent, have taken sharply different approaches to Ukraine.

Trump has for months criticised US support for Ukraine and derided Zelensky as a “salesman” for persuading Washington to provide weapons and funding to his military as it tries to fend off Moscow.

Friday's meeting almost wasn't scheduled despite Zelensky's office saying something had been planned during the Ukrainian leader's visit to the UN General Assembly, during which he is making his endgame pitch to allies.

In an interview with The New Yorker that was published earlier this week, Zelensky implied Trump does not understand and oversimplifies the conflict.