US President Donald Trump and Ukrainian President Volodymyr Zelensky held crunch war talks in the heart of the Vatican minutes before the start of the funeral of Pope Francis on Saturday, as the White House mounts an increasingly urgent push to strike a peace deal in Ukraine.

Donald Trump and Volodymyr Zelensky met briefly in the hush of St Peter's basilica before Pope Francis's funeral on Saturday in their first encounter since a noisy White House clash and the US president later cast doubt on whether Russian leader Vladimir Putin wants a peace deal.

The meeting between the two leaders at Pope Francis’s funeral was symbolic in part because of the Pope’s advocacy for a just end to the war in Ukraine.