Ukrainian President Volodymyr Zelensky says Ukraine's partners in Europe have not given him sound guarantees that they will defend Ukraine in the event of a fresh offensive by Russia.
"I continue to pose this critical question to every one of our allies and I have not received a clear, unambiguous answer yet," he told reporters on Wednesday.
These remarks follow a day after the UK and France inked a declaration of intent on deploying troops in Ukraine should a ceasefire agreement to conclude the conflict with Moscow is reached.
However, comprehensive defense assurances have yet to be solidified. The United States, which has been spearheading initiatives to end the invasion, reportedly did not sign such a commitment at talks in Paris on Tuesday.
Following the negotiations in Paris, which involved some 30 countries that comprise the group termed the 'Coalition of the Willing', British PM Keir Starmer said the UK and France would "set up operational bases across Ukraine" to deter future invasion, while France's President Macron subsequently indicated thousands of troops may be sent.
Allies proposed that the US would assume a leading role in monitoring a truce. But the central sticking point of territorial concessions that Ukraine is being pressured to offer to Russia as a component of the settlement terms are still being discussed.
The Russian government has not yet commented on the declaration made in the city of Paris.
Russian President Vladimir Putin initiated a full-scale invasion of Ukraine in February 2022, and Russian forces now occupies about one-fifth of Ukraine's land.
The UK Prime Minister characterized the joint statement as "a vital part of our dedication to stand with Ukraine for the foreseeable future".
He added: "It establishes the pathway for the legal framework under which allied military personnel could function on Ukraine's territory, securing Ukraine's skies and seas, and rebuilding Ukraine's armed forces for the future."
Zelensky hailed that agreement as a "huge step forward".
Twenty-four hours afterward, however, he appeared less optimistic.
"I perceive the determination, the political resolve, and that the allies are prepared, and the partners are ready to give us robust economic measures, strong security guarantees," he said when questioned if nations in Europe would defend Ukraine.
"But as long as we lack such security guarantees - formally ratified, supported by parliaments, supported by the United States Congress - this question remains unresolved. And even if they do, you still have to rely primarily on your own strength."
The Paris talks were also significant owing to the presence of envoys from former President Trump's administration, Steve Witkoff and Jared Kushner.
One envoy stated the allies "mostly completed" their work on agreeing security protocols.
Last week, Zelensky said a peace deal was "90% ready".
Territorial concessions and defense pledges have been at the center of outstanding matters for negotiators.
The Russian leader has consistently stated that Ukrainian troops must withdraw from the entirety of the Donbas region or Russia will seize it, rejecting any compromise over how to conclude hostilities.
Zelensky has so far ruled out relinquishing any land, but has suggested that Ukraine could withdraw its troops to an established line - but only if Russia did the same.
Russian forces now holds about 75% of the Donetsk region, and some 99% of the adjacent Luhansk region. The pair of oblasts form the industrial Donbas region.
It has been intensifying attacks against Ukrainian cities - particularly targeting energy infrastructure. Russia has also made slow progress in seizing additional Ukrainian land.
Ukrainian forces have retaliated at Russian targets with drones, though with more limited success.