Ukraine said Wednesday it wants its security to be guaranteed by international forces and rejected proposals pushed by Russia for it to adopt a neutral status comparable to Austria or Sweden.
"Ukraine is now in a direct state of war with Russia. As a result, the model can only be 'Ukrainian' and only on legally verified security guarantees," its top negotiator Mikhailo Podolyak said in comments published by President Volodymyr Zelensky's office.
He called for a legally binding security agreement, signed by international partners, who would "not stand aside in the event of an attack on Ukraine, as they do today."
The Kremlin earlier Wednesday said that a neutral Ukraine along the lines of Sweden or Austria was being discussed at talks with Kyiv to end three weeks of fighting in Ukraine.
"This is an option that is being discussed now and that can be considered as a compromise," Kremlin spokesman Dmitry Peskov told reporters.
His comments came after Foreign Minister Sergei Lavrov said neutrality was taking centre stage at the talks. Russia's lead negotiator had earlier introduced the proposal shot down by Ukraine.
Sweden officially is militarily non-aligned in peacetime and neutral in times of war, having ended its policy of neutrality in 1992 at the end of the Cold War.
It is not a member of NATO, but it has been a partner to the alliance for nearly 30 years.
At the end of the Cold War, Sweden slashed its military spending, but began reinvesting in its defence following Russia's annexation of the Crimean peninsula in 2014.
Russia and Ukraine have held several rounds of negotiations with the latest bout ending late Tuesday and Kyiv pointing to "fundamental contradictions".
Russia's foreign minister said earlier Wednesday that Moscow and Kyiv were "close to agreeing" the wording of an agreement on neutrality.
Both sides had earlier raised hopes of a breakthrough, referring to documents that were close to being put to paper and signed.
Russia's lead negotiator Vladimir Medinsky told reporters earlier Wednesday that talks were "slow and difficult" but said the Kremlin wants peace "as soon as possible."
Other than neutrality for Ukraine, Medinsky said issues including the status of the Crimean peninsula as well as territories held for years by pro-Moscow separatists were being discussed.