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.

The office of President Zelensky shared a picture of Trump and Zelensky engaged in conversation at St. Peter’s Basilica.

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.