Russia said it had to be part of any discussion on security guarantees for Ukraine and downplayed the likelihood of an imminent summit with Ukrainian President Volodymyr Zelensky, tempering hopes for a quick peace deal.
NATO military chiefs held a virtual summit on security guarantees for Ukraine, the latest in a flurry of global diplomacy aimed at brokering an end to the nearly three-and-a-half year conflict.
A small group of military leaders continued discussions in Washington, a source said.
The source said US General Dan Caine, chairman of the Joint Chiefs of Staff, held the talks that also involved around half a dozen other NATO chiefs of defence.
The official said the topic of security guarantees had not been discussed in detail at a video conference of all NATO chiefs of defence earlier in the day.
The source expected further meetings of the chiefs of defence in the broader format to be called, in order to discuss any options worked out in the smaller group.
No time frame has been set for discussions as the final decision will lie with political leaders, the official said.
Russia's Foreign Minister Sergei Lavrov warned that "seriously discussing security guarantees without the Russian Federation is a utopia, a road to nowhere".
Russia signed the Budapest Memorandum in 1994, which was aimed at ensuring security for Ukraine, Belarus and Kazakhstan in exchange for them giving up numerous nuclear weapons left from the Soviet era.
But Russia violated that first by taking Crimea in 2014, and then by starting a full-scale offensive in 2022, which has killed tens of thousands of people and forced millions to flee their homes.
Yesterday, top US officer Dan Caine, Chairman of the Joint Chiefs of Staff, held talks with European military chiefs on the "best options for a potential Ukraine peace deal," a US defence official said,
In eastern Ukraine, far from the diplomatic deliberations, Russian forces claimed fresh advances on the ground and Ukrainian officials reported more deaths from Russian attacks.
Diplomatic flurry
US President Donald Trump brought Mr Zelensky and European leaders to the White House Monday, three days after his landmark encounter with Russian President Vladimir Putin in Alaska.
Russia's long-serving foreign minister downplayed the meeting between Mr Trump and European leaders at the White House, describing it as a "clumsy" attempt to change the US president's position on Ukraine.
Mr Trump, long a fierce critic of the billions of dollars in US support to Ukraine, earlier said European nations were "willing to put people on the ground" to secure any settlement.
He ruled out sending US troops but suggested the country might provide air support.
Russia has long said it will never tolerate the presence of any Western troops in Ukraine.
While Mr Trump said Mr Putin had agreed to meet Mr Zelensky and accept some Western security guarantees for Ukraine, Russia has not confirmed this.
Mr Lavrov also cast doubt on an imminent meeting between the sworn enemies, saying that any summit between Mr Putin and Mr Zelensky "must be prepared in the most meticulous way" so it does not lead to a "deterioration" of the situation surrounding the conflict.
Fresh Russian strikes
Russia's defence ministry said Wednesday that its troops had captured the villages of Sukhetske and Pankivka in the embattled Donetsk region.
They are near a section of the front where the Russian army broke through Ukrainian defences last week, between the logistics hub of Pokrovsk and Kostiantynivka.
"Our units are engaged in heavy defensive battles against superior Russian forces," said Ukraine's commander-in-chief Oleksandr Syrsky.
Six civilians were killed by Russian attacks across eastern and southern Ukraine Wednesday, local authorities said.
One person died in Russia's western Bryansk region as a result of a Ukrainian drone strike, the local governor said.
Russia's aerial attacks on the northeastern town of Okhtyrka in the Sumy region wounded at least 14 people, including three children, according to regional governor Oleg Grygorov.
Mr Zelensky said these latest strikes showed "the need to put pressure on Moscow", including through sanctions.
