President Zelensky has stated that Ukraine's partners in Europe have not given him solid assurances that they will protect his country in the event of a fresh offensive by Russia.
"I am asking this very question to every one of our allies and I have not received a definitive and straightforward response yet," he stated to the press on midweek.
His comments come a day after Britain and France inked a declaration of intent on stationing forces in Ukraine if a peace deal to end the war with Russia is reached.
However, full security guarantees have not been agreed. The United States, which has been leading efforts to end the invasion, reportedly did not sign such a commitment at talks in Paris on Tuesday.
After the Paris talks, which involved some 30 countries that comprise the so-called Coalition of the Willing, British PM Keir Starmer said the two nations would "establish military hubs across Ukraine" to deter future invasion, while French President Emmanuel Macron subsequently indicated a significant number of soldiers may be deployed.
Allies proposed that the United States would assume a leading role in monitoring a truce. But the central sticking point of ceding land that Ukraine is being asked to grant to Russia as a component of the settlement terms are continuing to be negotiated.
The Russian government has not yet commented on the announcement made in the French capital.
President Putin launched a comprehensive military assault of Ukraine in February 2022, and Moscow currently controls about 20% of Ukraine's land.
The UK Prime Minister characterized the joint statement as "an essential component of our commitment to stand with Ukraine for the long-term".
He added: "It paves the way for the legal framework under which allied military personnel could function on Ukraine's territory, securing Ukraine's skies and seas, and regenerating Ukraine's military for the years to come."
The Ukrainian leader praised that agreement as a "huge step forward".
A day later, however, he appeared less optimistic.
"I see the will, 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 lack such binding security pacts - legally binding, endorsed by legislatures, supported by the United States Congress - this crucial issue cannot be answered. And should they materialize, you must ultimately depend primarily on your own strength."
The Paris talks were also notable owing to the attendance of envoys from former President Trump's administration, Jared Kushner and Steve Witkoff.
Witkoff said the allies "mostly completed" their work on finalizing security arrangements.
Recently, the President indicated a peace deal was "ninety percent complete".
Questions of land and security guarantees have been at the forefront of unresolved issues for negotiators.
The Russian leader has consistently stated that Ukrainian troops must withdraw from all of Ukraine's eastern Donbas or Russia will seize it, dismissing potential concessions over how to end the war.
The Ukrainian President has thus far rejected relinquishing any land, but has proposed that Ukraine could redeploy its forces to an agreed point - but only if Russia did the same.
Russian forces currently controls about 75% of the Donetsk region, and some 99% of the adjacent Luhansk region. The pair of oblasts constitute the industrial Donbas region.
It has been intensifying attacks against cities in Ukraine - particularly targeting energy infrastructure. Moscow is also achieving slow progress in capturing more Ukrainian territory.
Ukrainian forces have retaliated at objectives inside Russia with unmanned aerial vehicles, though with varying degrees of effectiveness.