Talks between US negotiators and Vladimir Putin about Ukraine were"productive" but there was no breakthrough, according to Russian officials.
Donald Trump sent special envoy Steve Witkoff and his own son-in-law, Jared Kushner, to Tuesday's summit in Moscow.
They were pictured in Red Square prior to the summit and Mr Witkoff later told a smiling Mr Putin that Moscow was a"magnificent city".
Shortly before the summit, the Russian president warned his country was ready to fight if Europe wanted a war.
Russian foreign policy aide Yuri Ushakov and investment envoy Kirill Dmitriev were involved in the talks, which lasted over five fours and ended after midnight.
Both sides agreed not to disclose precise details, but in a one-word social media post, Mr Dmitriev described the meeting as"productive".
Mr Ushakov called it"rather useful, constructive" and asked whether peace was closer or further, he commented:"Not further, that's for sure".
However, he said a compromise hadn't been reached on the issue of territories and that the Kremlin sees"no resolution to the crisis" without one.
Russia wants the whole of the Donbas region - even the parts it does not hold - but Ukraine has balked at the prospect.
Mr Ushakov said there was"still a lot of work to be done, both in Washington and in Moscow" and that "contacts will continue".
The meeting took place after an initial 28-point US peace plan was leaked and alarmed European officials, who said it heavily favoured Russia.
An"updated and refined peace framework" was formulated after talks between Europe, the US and Ukraine in Geneva last month.
Earlier on Tuesday, Mr Putin said Russia was ready to fight if Europe wanted a war.
The Russian president accused European powers of changing peace proposals for Ukraine with"demands" that Russia considered "absolutely unacceptable".
Mr Putin said the Europeans were"on the side of war".
"We're not planning to go to war with Europe, I've said that a hundred times," he said following an investment forum.
"But if Europe suddenly wants to fight us and starts, we're ready right now. There can be no doubt about that."
"If Europe suddenly wants to start a war with us and does, then a situation could very quickly arise in which we have no one to negotiate with," he added.
Zelenskyy in Dublin
Ukraine's President Volodymyr Zelenskyy was in Dublin on Tuesday to meet Ireland's prime minister and president.
During the trip, Mr Zelenskyy said he was ready to meet Mr Trump again but it would depend on how successful the Moscow talks were.
He said the chances of ending the war were"better now than ever" but warned there would be "no easy decisions" and there must be "no games behind Ukraine's back".
Calling it"one of the most challenging but optimistic moments" since Russia invaded in 2022, he said the US was"taking serious steps to end this war one way or another".
He admitted"some things still need to be worked out" and said a "decent, dignified peace" was needed.
The Irish government announced €100m (£88m) in non-lethal aid for Ukraine,"generosity" for which Mr Zelenskyy said Ukraine was grateful.
It brings the total in non-lethal military aid provided to Ukraine this year to €200m (£176m).
The funding is part of a new Ireland-Ukraine partnership, which builds on an agreement signed last year.
It includes €25m (£22m) for the restoration and protection of energy infrastructure and a scheme to support training and other efforts as part of Ukraine's path to EU accession, which Mr Zelenskyy said he hoped to achieve within five years.
