Ukrainian President Volodymyr Zelensky says European allies have failed to provide solid assurances that they will defend Ukraine in the case of a fresh offensive by Russia.
"I am asking this very question to every one of our allies and thus far, the answer remains elusive a clear, unambiguous answer yet," he told reporters on midweek.
His comments come a day after Britain and France inked a declaration of intent on deploying troops in Ukraine should a ceasefire agreement to end the war with Russia is finalized.
However, full security guarantees have yet to be solidified. The US, which has been leading efforts to end the invasion, was reported to have abstained from signing such a commitment at discussions held in the French capital on the previous day.
Following the negotiations in Paris, which involved some 30 countries that comprise the so-called Coalition of the Willing, British PM Keir Starmer said the UK and France would "establish military hubs across Ukraine" to deter future invasion, while French President Emmanuel Macron later said 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 asked to grant to Russia as a component of the settlement terms are continuing to be negotiated.
Moscow has not yet commented on the announcement made in the city of Paris.
President Putin launched a full-scale invasion of Ukraine in the early months of 2022, and Russian forces currently controls about one-fifth of Ukraine's land.
The UK Prime Minister characterized the joint statement as "an essential component of our dedication to stand with Ukraine for the foreseeable future".
He continued: "It establishes the pathway for the legal framework under which British, French and partner forces could function on Ukraine's territory, securing Ukraine's skies and seas, and regenerating Ukraine's armed forces 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 resolve, 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 come to Ukraine's aid.
"However, until we lack such security guarantees - legally binding, supported by parliaments, supported by the United States Congress - this crucial issue cannot be answered. And should they materialize, you must ultimately depend first and foremost on your own strength."
Negotiations in Paris were also notable owing to the attendance of US President Donald Trump's peace envoys, Steve Witkoff and Jared Kushner.
Witkoff said the allies "mostly completed" their work on agreeing security protocols.
Last week, Zelensky said a settlement was "90% ready".
Questions of land and security guarantees have been at the forefront of unresolved issues for diplomats.
The Russian leader has consistently stated that Ukrainian troops must pull back from all of Ukraine's eastern Donbas or Russia will seize it, rejecting any compromise over how to conclude hostilities.
The Ukrainian President has thus far rejected relinquishing any land, but has suggested that Ukraine could redeploy its forces to an agreed point - but provided that Russia reciprocated the action.
Moscow currently controls about 75% of the Donetsk region, and some 99% of the adjacent Luhansk region. The two regions form the industrial Donbas region.
It has been intensifying attacks against Ukrainian cities - with a focus on power facilities. Moscow is also achieving slow progress in seizing additional Ukrainian land.
Ukrainian forces have retaliated at Russian targets with unmanned aerial vehicles, though with varying degrees of effectiveness.