President Zelensky has stated that Ukraine's partners in Europe have failed to provide sound guarantees that they will defend Ukraine in the case of a future Russian attack.
"I continue to pose this critical question to every one of our allies and thus far, the answer remains elusive a definitive and straightforward response yet," he told reporters on midweek.
These remarks follow a day after the UK and France inked a statement of purpose on deploying troops in Ukraine should a ceasefire agreement to conclude the conflict with Moscow is agreed.
However, full security guarantees have yet to be solidified. The US, which has been spearheading initiatives to halt the offensive, was reported to have abstained from signing such a commitment at talks in Paris on Tuesday.
After the Paris talks, which included some 30 countries that comprise the so-called Coalition of the Willing, UK Prime Minister Sir Keir Starmer said the two nations would "establish military hubs across Ukraine" to deter future invasion, while France's President Macron subsequently indicated thousands of troops may be sent.
Allies proposed that the United States would take the lead in monitoring a truce. But the key issue of ceding land that Ukraine is being pressured to offer to Russia as a component of the settlement terms are still being discussed.
Moscow has thus far remained silent 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 currently controls about one-fifth of Ukrainian territory.
The UK Prime Minister characterized the bilateral declaration as "a vital part of our dedication to stand with Ukraine for the foreseeable future".
He continued: "It paves the way for the juridical structure under which allied military personnel could function on Ukrainian soil, securing Ukraine's skies and seas, and rebuilding Ukraine's armed forces for the years to come."
Zelensky hailed that accord as a "huge step forward".
A day later, however, he appeared less optimistic.
"I perceive the determination, the political will, and that the partners are ready, and the allies are willing to give us strong sanctions, strong security guarantees," he said when questioned if European countries would defend Ukraine.
"However, until we don't have such security guarantees - legally binding, supported by parliaments, backed by the U.S. Congress - this question remains unresolved. And even if they do, you must ultimately depend first and foremost on your inherent capabilities."
Negotiations in Paris were also notable due to the presence of envoys from former President Trump's administration, Jared Kushner and Steve Witkoff.
Witkoff said the participating countries "mostly completed" their work on finalizing security arrangements.
Recently, Zelensky said a settlement was "ninety percent complete".
Questions of land and defense pledges have been at the center of unresolved issues for negotiators.
Putin has repeatedly warned that Ukraine's military must pull back from the entirety of the Donbas region or Moscow will take control, rejecting any compromise over how to conclude hostilities.
Zelensky has so far ruled out ceding any territory, but has suggested that Ukraine could redeploy its forces to an agreed point - but only if Russia did the same.
Russian forces now holds about three-quarters of the Donetsk region, and some 99% of the adjacent Luhansk region. The two regions form the industrial Donbas region.
Attacks have been escalating against Ukrainian cities - particularly targeting power facilities. Russia has also made slow progress in seizing additional Ukrainian land.
Ukrainian forces have retaliated at objectives inside Russia with unmanned aerial vehicles, though with varying degrees of effectiveness.