Trump has repeatedly complained that ending Europe's deadliest conflict since World War II has been one of the elusive foreign policy aims of his presidency. The US president has at times scolded both Putin and Ukrainian President Volodymyr Zelenskiy.
Talks in Moscow between Putin and Trump's special envoy, Steve Witkoff, and son-in-law Jared Kushner went past midnight. Afterward, Putin's top foreign policy aide, Yuri Ushakov, said: "Compromises have not yet been found."
He said peace is no closer but described the talks as "rather useful, constructive, rather substantive."
"There is still a lot of work to be done," Ushakov told reporters at a briefing in the Kremlin.
Putin reacted negatively to some US proposals, Ushakov said. Witkoff went to the US embassy in Moscow after the talks to brief the White House, Ushakov said.
Ushakov added that a meeting between Putin and Trump was not currently planned, though he said the talks were constructive and that there were huge opportunities for US-Russian economic co-operation.
Ushakov said Putin had sent a series of important signals and his greetings to Trump, but that the sides had agreed not to disclose details to the media.
He added they had discussed the "territorial problem", Kremlin shorthand for Russian claims to the whole of Donbas, though Ukraine controls at least 5000 square km of the area which Russia claims as its own. Almost all countries recognise Donbas as part of Ukraine.
"Some American draft proposals look more or less acceptable, but they need to be discussed," Ushakov said.
"Some of the formulations that have been proposed to us are not suitable for us, that is - the work will continue."
Witkoff, a billionaire US real estate developer who has known Trump since the 1980s, and Kushner, the husband of Trump's daughter Ivanka, began talks in the Kremlin after a stroll across Red Square past the mausoleum of Soviet founder Vladimir Lenin to the towers of the Kremlin.
They talked with Putin, Ushakov and Putin's envoy Kirill Dmitriev, via interpreters.
"Our people are over in Russia right now to see if we can get it settled. Not an easy situation, let me tell you. What a mess," Trump said in Washington, adding that there were casualties of 25,000 to 30,000 per month in the war.
Russia invaded Ukraine in February 2022, triggering the biggest confrontation between Moscow and the West since the depths of the Cold War.
A leaked set of 28 US draft peace proposals emerged in November, alarming Ukrainian and European officials who said it bowed to Moscow's main demands.
European powers then came up with a counter-proposal, and at talks in Geneva, the US and Ukraine said they had created an "updated and refined peace framework" to end the war.
Zelenskiy, speaking in Dublin, said everything would depend on the talks in Moscow but that he was afraid the US could lose interest in the peace process.
"There will be no easy solutions ... It is important that everything is fair and open, so that there are no games behind Ukraine's back," he said.
Just before the Kremlin meeting with Witkoff, Putin said Russia did not want war with Europe, but that if Europe started one, it would end so swiftly that there would be no one left for Russia to negotiate with.
Putin threatened to sever Ukraine's access to the sea in response to drone attacks on tankers of Russia's "shadow fleet" in the Black Sea. Ukraine's Foreign Minister, Andrii Sybiha, said Putin's remarks showed he was not ready to end the war.
