LONDON/PARIS — Talks among US, Ukrainian and European officials on ending the Russia-Ukraine conflict faltered on Wednesday as US Secretary of State Marco Rubio abruptly canceled his trip to London, downgrading the negotiations.

Rubio's no-show prompted a broader meeting of foreign ministers from Ukraine, the United Kingdom, France and Germany to be canceled, though talks continued at a lower level. The United States would now be represented by Ukraine envoy Keith Kellogg.

The downgrading of the talks came at a critical time, just days after US President Donald Trump warned that Washington could walk away if there was no progress on a deal soon.

A source close to the discussions said the downgrading of the meeting came after Ukraine drafted a paper for the Europeans on Tuesday in which it said there would be no discussions on territorial issues until "a full and unconditional ceasefire".

The source said the apparent US nervousness could indicate that the Ukrainian position did not align with what Washington's representatives had agreed so far with the Russians.

US Vice-President JD Vance, during a visit on Wednesday to Agra, India, told reporters,"We've issued a very explicit proposal to both the Russians and the Ukrainians, and it's time for them to either say yes or for the United States to walk away from this process."

He said it was "a very fair proposal" that would "freeze the territorial lines at some level close to where they are today", with both sides having to give up some territory they currently hold. He did not provide further details of the proposal.

Vance's comments came a day after Ukrainian President Volodymyr Zelensky ruled out ceding territory to Russia as part of any potential peace agreement, calling it a nonstarter.

The London meeting is a follow-up to a similar session in Paris last week where US, Ukrainian and European officials discussed ways to move forward and narrow down differences.

During those talks, Trump's special envoy Steve Witkoff presented a paper to the participants outlining proposals in which Ukraine in particular, but also Russia, would need to make concessions, according to three diplomats aware of the talks.

Witkoff is to visit Moscow this week, the White House has confirmed, in what would be his fourth trip to Russia since Trump took office.

'Fake' reports

According to the Financial Times, Russian President Vladimir Putin told Witkoff he was prepared to halt the military operation and freeze the current front line if Russia's sovereignty over the Crimean Peninsula was recognized.

Kremlin spokesman Dmitry Peskov responded on Wednesday by saying that "a lot of fakes are being published at the moment", according to the RIA Novosti state news agency.

The London talks were aimed at working to bridge differences and find areas that could satisfy Moscow and open a serious negotiation, diplomats said.

Beyond Crimea, other major sticking points remain, including Russia's push for lifting of European Union sanctions against it before negotiations are finished — which Europe staunchly opposes, diplomats said.

The Kremlin said on Wednesday that countries involved in peace talks around Ukraine still needed to narrow down their differences and that there were "a lot of nuances" that needed to be worked out before any deal could be reached.

"We are also continuing our contacts ... but of course there are many nuances around the settlement that need to be worked out, where positions need to be brought closer together and so on. This work is ongoing," Peskov told reporters.

He said Russia was continuing to talk to the US about a possible settlement, but was not in contact with Europe or Ukraine on the subject. However, Putin remained open to talks with all parties, he added.

Agencies via Xinhua