Ukraine is preparing to present a revised peace plan to the White House, as it seeks to avoid making territorial concessions to Russia.
Kyiv is set to propose alternatives to the US after President Volodymyr Zelensky again ruled out surrendering land, saying he had 'no right' to do so under Ukrainian or international law.
He made the comments as he met European and NATO leaders on Monday, part of a collective push to deter the US from backing a peace deal which includes major concessions for Ukraine, and which allies fear would leave it vulnerable to a future invasion.
Meanwhile, the city of Sumy in northwestern Ukraine was left without power overnight after a Russian drone attack.
The region's governor said more than a dozen drones had hit power infrastructure, the latest in Russia's nightly attacks. No deaths were reported.
Zelensky's ongoing diplomatic tour of Europe follows days of intensive talks between US and Ukrainian negotiators over the weekend that failed to produce a deal Kyiv could agree to.
Zelensky was due to be briefed on that private summit on Monday by his chief aide Rustem Umerov, who wrote on Telegram that he would feed back details of direct talks between the US and Russian President Vladimir Putin.
The Ukrainian president told a news conference that his team could send a new proposal to the Americans as soon as Tuesday, AFP news agency reported.
On the subject of surrendering land, Zelensky said: Russia is insisting that we give up territories, but we don't want to cede anything.
He continued: We have no legal right to do so, under Ukrainian law, our constitution and international law. And we don't have any moral right either.
Zelensky has long maintained that any changes to Ukraine's borders would need to be authorized by a public referendum.
Elsewhere, he told reporters that the initial 28-point plan proposed by the US - and rejected by Kyiv and European leaders as being too favorable to Russia - had been cut down to 20 points, according to Interfax-Ukraine news agency.
He said no pro-Ukrainian points had been removed from the draft, though there had also been no compromise on the subject of territory.
Zelensky highlighted control of the eastern Donbas region and the Zaporizhzhia nuclear power plant as among the most sensitive issues.
Leaders in Kyiv and across Europe have indicated that progress has been made in refining that draft in recent weeks and have praised the Trump administration for seeking to mediate an end to the fighting.
But Monday's hastily arranged Downing Street summit - attended by Zelensky, UK Prime Minister Sir Keir Starmer, French President Emmanuel Macron and German Chancellor Friedrich Merz - was widely viewed as a show of support for Ukraine amid pressure from the White House.
No 10 reported an agreement that the US-led talks represented a critical moment for ramping up support for Ukraine, reiterating calls for a just and lasting peace... which includes robust security guarantees.
The future nature of those guarantees remains uncertain as discussions continue to devise an international coalition for military support in the event of a peace deal. Proposals for deploying international troops have been contested among European defense players.
Following talks in London, Zelensky moved on to Brussels to meet NATO chief Mark Rutte and EU chief Ursula von der Leyen, with a meeting scheduled in Italy with Prime Minister Georgia Meloni on Tuesday.
Moscow has claimed that talks with the White House have been constructive, despite a lack of public movement on Kremlin goals since the invasion in February 2022.
On Sunday, Trump suggested Zelensky is a pivotal figure in achieving a peace deal, which he views as a key foreign policy objective in the upcoming 2024 presidential election.
He stated that Russia has shown willingness for peace, contrasting it with Zelensky's stance, although the accuracy of his claims remains unclear.
