In the run-up to his US election victory, Trump declared many times that he would have a deal in place between Ukraine and Russia on his first day in office, if not before.
His advisers now concede the war will take months to resolve.
"I really would like to be able to meet with President Putin soon to get that war ended," Trump, who returned to the White House on Monday, told the World Economic Forum in Davos by video link.
"And that's not from the standpoint of economy or anything else. It's from the standpoint of millions of lives are being wasted ... It's a carnage. And we really have to stop that war."
US President Donald Trump says the Ukraine war needs to end as "millions of lives are being wasted". (AP PHOTO)
Trump also said US efforts to secure a peace settlement were now hopefully under way but gave no details.
Russia invaded Ukraine in February 2022.
Earlier this week, Trump threatened to impose "high levels" of sanctions on Russia and tariffs on imports from there if the Kremlin did not reach a settlement.
Trump also told the crowd on Thursday he wants to work towards cutting nuclear arms, adding that he thought Russia and China might support reducing their own weapons capabilities.
"We'd like to see denuclearisation ... and I will tell you President Putin really liked the idea of cutting way back on nuclear. And I think the rest of the world, we would have gotten them to follow, and China would have come along too," Trump said.
Ukrainian officials praised Trump on Thursday for threatening to impose tariffs and sanctions on Russia if it refuses to make a deal to end the war.
"We do really welcome such strong messages from President Trump and we believe that he will be the winner. And we believe that we have an additional chance to get new dynamic in diplomatic efforts to end this war," Ukraine's Foreign Minister Andrii Sybiha said, speaking in English at a discussion panel in Davos.
The Kremlin said it saw nothing particularly new in Trump's threat but that it was following closely "all nuances" in his rhetoric and remained open to dialogue.
Ukraine's air force said it fought off a Russian drone attack overnight. (AP PHOTO)
Separately Russian air defences repelled a massive Ukrainian drone attack overnight, intercepting and destroying 121 drones targeting 13 regions, including Moscow, Russia's Defence Ministry said, making no mention of casualties or damage.
The ministry said six drones had been destroyed over the Moscow region and one over the capital itself, while other drones had targeted other regions, including those that border Ukraine and Kursk, where Ukrainian troops hold a chunk of land despite Russian efforts to eject them.
Twenty drones had also targeted the Ryazan region, southeast of Moscow, the ministry said, and channels on the Telegram messaging app posted unverified videos of what bloggers there described as large blazes in the city. They said an oil storage depot and a power station had been hit.
Meanwhile, Ukraine's air force said on Friday it had also fought off a Russian drone attack had shot down 25 of 58 drones launched by Russia in an overnight assault.
Ukraine's interior ministry said drone debris had killed two men and a woman in the central Kyiv region, and that another person had been injured.
