"I want to be clear -- Russia has to withdraw from every square meter of Ukrainian territory. There should be no misinterpretation of what the word withdrawal implies," Foreign Minister Dmytro Kuleba told a virtual session with counterparts as part of the second US-led Summit for Democracy.

President Joe Biden will formally kick off the summit on Wednesday as part of his effort to rally against Russia as well as China's growing inroads.

"In this fight, we are defending the entire democratic world," Kuleba said.

China has put forward a proposal, embraced by Russian President Vladimir Putin, for a ceasefire, which has been dismissed by Ukraine and its Western backers as a way to freeze Moscow's gains from the 13-month-old invasion.

Ukrainian President Volodymyr Zelensky has also stood firm on sovereignty over Crimea, the peninsula which Russia seized and declared it annexed in 2014.

"No other nation wants peace more than Ukraine. But peace at any cost is an illusion. For peace to be a lasting one, it needs to be just," Kuleba said.

"The cessation of Russia's aggression and the restoration of Ukraine's territorial integrity are essential conditions for peace.

"Ill-advised concessions to the aggressor would only encourage Russia to intensify its attacks on democracy, giving it time to rebuild its military capabilities and resume the armed offensive against Ukraine."

US Secretary of State Antony Blinken, who led the session, backed the Ukrainian proposals and warned again of any settlement that would simply let Russian forces regroup.

"This war can of course end tomorrow if President Putin so chose by withdrawing Russian forces from Ukraine," Blinken said.