Ukraine's presidency has said that the country did not expect to take part in talks with Russian officials at the Munich security conference, as announced by US President Donald Trump.
"A common position (with allies) must be on the table for a conversation with the Russians. For the moment there is nothing on the table. Discussions with the Russians are not envisaged," Dmytro Lytvyn, an advisor to President Volodymyr Zelensky, told reporters.
It comes after US President Donald Trump said Ukraine will be "part of" negotiations on ending Russia's brutal three-year-old war in the country.
Mr Trump spoke a day after he announced plans to begin peace talks, following separate telephone calls Wednesday with Russian President Vladimir Putin and his Ukrainian counterpart Volodymyr Zelensky.
The US President said he is convinced the Russian leader "wants peace" adding "I think he would tell me if he didn't."
Mr Zelensky earlier warned leaders not to trust Mr Putin's claims to want peace.
In a post on social media following a call with Polish Prime Minister Donald Tusk, Mr Zelensky said he had "warned world leaders against trusting Putin's claims of readiness to end the war".
He wanted to agree a position with the United States to "stop Putin" before holding any peace talks with Russia.
Mr Trump held a long phone call with Mr Vladimir Putin yesterday and said the sides had agreed to begin negotiations on Ukraine "immediately". Mr Zelensky and senior Ukrainian officials are undertaking a series of meetings this week with Trump allies in Kyiv and Brussels and at the Munich Security Conference.
"The Ukraine-America meetings are a priority for us," said Mr Zelensky.
"And only after such meetings, after a plan to stop Putin has been worked out, I think it is fair to talk to the Russians."
Mr Trump also spoke with Mr Zelensky in a call that the Ukrainian leader had described as "meaningful" and broad.
But he said that while he believed Ukraine was Mr Trump's priority, it was "not very pleasant" that the US leader had spoken with Mr Putin first.
The Ukrainian leader also said that Mr Trump had told him he had wanted to speak with both Mr Putin and him at the same time, without elaborating on why that had not happened.
Mr Zelensky also said he had told Mr Trump that without security guarantees Russia was likely to attack Ukraine again.
'Simply will not be able to accept any agreements without us'
Ukraine and its European allies have been demanding that they be included in any peace negotiations.
But Mr Trump's unilateral overture to Mr Putin, accompanied by apparent concessions on Ukraine's principal demands, have raised alarm for both Kyiv and the European allies in NATO who said they feared the White House might make a deal without them.
"We, as a sovereign country, simply will not be able to accept any agreements without us," Mr Zelensky said.
He said Mr Putin aimed to make his negotiations bilateral with the United States, and it was important not to allow that.
European officials took an exceptionally firm line in public towards Mr Trump's peace overture, saying any agreement would be impossible to implement unless they and the Ukrainians were included in negotiating it.
"Any quick fix is a dirty deal," European foreign policy chief Kaja Kallas said. She also strongly denounced the apparent concessions offered in advance.
"Why are we giving them (Russia) everything that they want even before the negotiations have been started?" said Ms Kallas. "It's appeasement. It has never worked."
A European diplomatic source said ministers had agreed to engage in a "frank and demanding dialogue" with US officials - some of the strongest language in the diplomatic lexicon – at the annual Munich Security Conference beginning tomorrow.
Mr Trump, who made the first publicly acknowledged White House call with Mr Putin since the February 2022 full-scale invasion, and then followed it up with a call to Mr Zelensky, said he believed both men wanted peace.
But the Trump administration also said openly for the first time that it was unrealistic for Ukraine to expect to return to its 2014 borders or join the NATO alliance as part of any agreement, and that no US troops would join any security force in Ukraine that might be set up to guarantee a ceasefire.
US Defense Secretary Pete Hegseth said he world was fortunate to have Mr Trump, the "best negotiator on the planet, bringing two sides together to find a negotiated peace".
The Kremlin, for its part, said it was "impressed" by Mr Trump's position, which it contrasted with that of his predecessor Joe Biden.
"There is a political will, which was emphasised during yesterday's conversation, to conduct a dialogue in search of a settlement," Kremlin spokesman Dmitry Peskov said.
Russia seized Ukraine's Crimea peninsula and its proxies captured territory in the east in 2014, before its full-scale invasion in 2022 when it captured more land in the east and south.
Ukraine pushed Russian troops back from the outskirts of Kyiv and recaptured swathes of territory in 2022, but its outmanned and outgunned forces have slowly ceded more land since a failed Ukrainian counter-offensive in 2023.
Relentless fighting has killed or injured hundreds of thousands of troops on both sides - there is no reliable death toll - and pulverised Ukrainian cities.
Through years of fighting there has been no narrowing of positions on either side. Moscow demands Kyiv cede more land and be rendered permanently neutral in any peace deal; Kyiv says Russian troops must withdraw and it must win security guarantees equivalent to NATO membership to prevent future attacks.
Ukrainian officials have acknowledged in the past that full NATO membership may be out of reach in the short term and that a hypothetical peace deal could leave some occupied land in Russian hands.
But Kyiv and its European allies made clear they were alarmed by Mr Trump having opened negotiations with apparent concessions to Moscow, without first agreeing a common position.
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Ukraine's Foreign Minister Andrii Sybiha said Kyiv remained committed to applying to join NATO, which he said was the simplest and least expensive way the West could provide the security guarantees needed to ensure peace.
"All our allies have said the path of Ukraine towards NATO is irreversible. This prospect is in our constitution. It is in our strategic interest."
The mood in Ukraine's capital was downbeat.
Kyiv resident Myroslava Lesko, 23, standing near a sea of flags downtown honouring fallen troops, said: "It truly looks as if they want to surrender Ukraine, because I don't see any benefits for our country from these negotiations or Trump's rhetoric."
However, Ukrainians have been worn out by three years of war, and many say they are prepared to sacrifice some aims to achieve peace.
Many were frustrated by US policy under Mr Biden, who had vowed to help Ukraine win all its land back and provided tens of billions of dollars worth of military hardware, but with restrictions and delays that Ukrainian commanders say allowed Russian forces to regroup.
Mr Trump, at least, is being more forthright about the limits of US support, said Tymofiy Mylovanov, president of the Kyiv School of Economics.
