Donald Trump and Volodymyr Zelensky met briefly at Pope Francis' funeral on Saturday, their aides said, marking their first encounter since a disastrous White House clash as the US president pushes the Ukrainian to make a peace deal with Russia. 

Trump was rubbing shoulders with dozens of world leaders at St Peter's Basilica in Rome keen to bend his ear on the tariffs he has unleashed and other subjects. 

But it was the meeting with Zelensky that drew the most interest as the US leader pushes the Ukrainian to make a peace deal with Russia. 

The two leaders met briefly on the sidelines of the funeral before it started, a spokesman for the Ukrainian presidency said.

"The meeting took place and is already over," Zelensky's spokesman Sergiy Nykyforov told journalists without providing further detail.

White House communications director Steven Cheung also confirmed the meeting occured, calling it "a very productive discussion" and saying more details would follow. 

Trump and Zelensky, both accompanied by their wives, sat in the front row of the funeral in St Peter's Square but were separated by nearly a dozen leaders. Zelensky glanced Trump's way but they were not seen to meet in public.

Both sides had kept the prospects of a meeting vague ahead of the funeral with Trump saying only it was "possible."

Tensions have been high since Trump and Vice President JD Vance berated Zelensky in the Oval Office on February 28, calling him ungrateful for the billions of dollars of US military assistance given since Russia invaded Ukraine in 2022.

Blame game

Trump, while calling on President Vladimir Putin to stop Russia's attacks on Ukraine, has recently blamed Zelensky for the war and the continuing bloodshed.

Russia launched a large-scale invasion of Ukraine in February 2022, triggering a conflict not seen in Europe for decades.

Trump has also pushed Zelensky to accept previously unpalatable concessions such as acknowledging that Crimea, which Moscow seized from Ukraine in 2014, will remain in Russian hands under any deal to stop the conflict.

Arriving in Rome late Friday, Trump pushed for the Russian and Ukrainian leaders to meet after what he said was progress in talks.

"They are very close to a deal, and the two sides should now meet, at very high levels, to 'finish it off,'" he posted on his Truth Social platform.

"Most of the major points are agreed to," he said.

Putin on Friday discussed the "possibility" of direct talks with Ukraine in a meeting with US envoy Steve Witkoff.

But Zelensky again rejected suggestions that Ukraine give up Crimea. 

Witkoff's meeting with Putin came just after a top Russian general was killed in a car bomb attack outside Moscow.

An increasingly frustrated Trump last week threatened to walk away from peace efforts if he does not see progress towards a ceasefire.

Trump last year promised to end the Ukraine war within 24 hours if elected president, though he said in a Time magazine interview this week that he was speaking "in jest."

Few meetings

The US president, accompanied by his wife Melania, is making the first foreign trip of his second term.

It puts him center-stage for a major diplomatic gathering with some 50 heads of state, including 10 reigning monarchs, and Britain's Prince William.

Trump's trip to Italy also comes after he rattled European allies by imposing sweeping tariffs, although he at least temporarily has backed down from the most severe measures.

The US president shook hands with EU chief Ursula von der Leyen. He also greeted French President Emmanuel Macron, a close ally.

Other leaders also swarmed Trump after he arrived. 

One person he did not meet: his predecessor Joe Biden. Trump has repeatedly disparaged Biden, a devout Catholic attending independently with wife Jill and sitting five rows behind his successor.

Previously, other presidents have taken their predecessors with them on Air Force One to papal funerals.

Official Vatican images showed Trump and Melania stopping by the closed coffin in St. Peter's Basilica after his motorcade had arrived at the Vatican.

Trump, in a dark blue suit and tie, and Melania, wearing a black veil, then took their seats in the front row for the service.

Trump earlier said any meetings would be quick and added, "Frankly it's a little disrespectful to have meetings when you're at the funeral of the pope."

He is due to fly back to the United States later Saturday after just half a day in the Eternal City.