Zelensky said Tuesday that Russia can only be forced into a peace settlement and vowed not to negotiate on Moscow's terms to end the conflict.

Kremlin spokesman Dmitry Peskov told reporters Wednesday that "such a position is a fatal mistake, a systemic mistake."

"It is a profound misconception that will inevitably have consequences for the Kyiv regime," he added.

"Russia is in favour of peace, but with the conditions that its stability is ensured and the objectives of the special military operation are fulfilled," he added, using Moscow's official language for the Ukraine campaign.

"Without the achievement of these goals, it is impossible to coerce Russia," Peskov said.

Zelensky is in the United States this week hoping to boost international backing for Kyiv.

"We know some in the world want to talk" to Russian President Vladimir Putin, Zelensky told the UN on Tuesday.

Clad in his trademark military fatigues, he called such views "insanity."

"Russia can only be forced into peace, and that is exactly what's needed -- forcing Russia into peace," he added.

More than two and a half years after Russia launched its full-scale military offensive, the two sides appear as far apart as ever when it comes to a possible deal to end the fighting.

Kyiv launched a shock counter-offensive into Russia's western Kursk region last month, the first assault on Russian territory by a foreign army since World War II.

Moscow has demanded Kyiv abandon territory it currently controls in the east and south of Ukraine as a precondition for peace talks.