President Zelensky has stated that Ukraine's partners in Europe have not given him solid assurances that they will protect his country in the case 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 midweek.
His comments come a day after the UK and France inked a statement of purpose on deploying troops in Ukraine should a ceasefire agreement to end the war with Russia is reached.
However, full security guarantees have yet to be solidified. The United States, which has been spearheading initiatives to end the invasion, reportedly did not sign such a pledge at discussions held in the French capital on Tuesday.
After the Paris talks, which involved some three dozen nations that comprise the so-called Coalition of the Willing, British PM Keir Starmer said the two nations would "set up operational bases across Ukraine" to prevent any future incursion, while France's President Macron later said a significant number of soldiers may be deployed.
Partner nations suggested that the United States would take the lead in overseeing any ceasefire. But the key issue of ceding land that Ukraine is being pressured to offer to Russia as a component of the settlement terms are continuing to be negotiated.
The Russian government has thus far remained silent on the declaration made in the French capital.
President Putin launched a comprehensive military assault 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 added: "It establishes the pathway for the juridical structure under which allied military personnel could function on Ukraine's territory, protecting Ukrainian airspace and waters, and rebuilding Ukraine's armed forces for the years to come."
Zelensky hailed that agreement as a "huge step forward".
Twenty-four hours afterward, 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 robust economic measures, powerful defense assurances," he said when questioned if nations in Europe would come to Ukraine's aid.
"But as long as we lack such binding security pacts - legally binding, endorsed by legislatures, supported by the United States Congress - this crucial issue remains unresolved. And should they materialize, you must ultimately depend primarily on your inherent capabilities."
Negotiations in Paris were also significant due to the presence of envoys from former President Trump's administration, Jared Kushner and Steve Witkoff.
Witkoff said the allies "largely finished" their work on agreeing security protocols.
Last week, Zelensky said a settlement was "ninety percent complete".
Questions of land and defense pledges have been at the center of unresolved issues for negotiators.
The Russian leader has consistently stated that Ukraine's military must withdraw from the entirety of the Donbas region or Moscow will take control, dismissing potential concessions over how to conclude hostilities.
Zelensky has so far ruled out ceding any territory, but has proposed that Ukraine could redeploy its forces to an agreed point - but provided that Russia did the same.
Russian forces currently controls about 75% of the Donetsk region, and some 99% of the neighbouring Luhansk. The pair of oblasts constitute the Donbas industrial heartland.
It has been intensifying attacks against cities in Ukraine - particularly targeting energy infrastructure. Russia has also made slow progress in capturing more Ukrainian territory.
Ukraine has hit back at Russian targets with unmanned aerial vehicles, albeit with varying degrees of effectiveness.
Lena is a tech journalist with over a decade of experience covering consumer electronics and emerging technologies.