Donald Trump has said the Ukrainian president can end Russia's war "if he wants to", but there would be "no going into Nato by Ukraine" as part of a peace deal, BBC reported.

Hours before he was due to host Volodymyr Zelensky at the White House, Trump also said there would be "no getting back" of the Crimean peninsula, which Moscow illegally annexed in 2014, eight years before launching its full-scale invasion.

Trump's remarks follow his summit with Russian leader Vladimir Putin in Alaska that resulted in the US president dropping a demand for a ceasefire and calling instead for a permanent peace deal.

After arriving in the US late on Sunday, Zelensky reiterated his call for allies' effective security guarantees, according to BBC.