Ukrainian President Volodymyr Zelensky dismissed a three-day truce ordered by Russian leader Vladimir Putin as theatrics but said Kyiv was ready for a full ceasefire.

Russia has so far rejected an unconditional 30-day ceasefire pushed by Kyiv and Washington, which is trying to broker an end to the three-year Russian invasion of Ukraine.

"This is more of a theatrical performance on his part. Because in two or three days, it is impossible to develop a plan for the next steps to end the war," Zelensky said.

Zelensky was speaking on Friday to a small group of journalists including AFP, in remarks embargoed until yesterday.

Zelensky said Ukraine would not be "playing games to create a pleasant atmosphere to allow for Putin's exit from isolation on 9 May," when some foreign leaders are due in Moscow for Russian World War II commemorations.

Ukraine has hit Moscow several times during the invasion, as well as targets across Russia.

Leaders of around 20 countries, including China's Xi Jinping, have accepted invitations to join this year's celebration, according to the Kremlin.

Zelensky said some countries had approached Kyiv, warning they were travelling to Russia and had requested safety.

"Our position is very simple towards all countries that have travelled or are travelling to Russia on May 9 -- we cannot take responsibility for what is happening on the territory of the Russian Federation," he answered.

"They are ensuring your safety," Zelensky said, adding that Russia "may take various steps on its part, such as arson, explosions, and so on and then blame us."

Russian officials have promised grand celebrations for the occasion, during which Putin will seek to rally support for his troops fighting in Ukraine.

In reply, the Kremlin yesterday said it wanted a definitive response from Ukraine to Putin's offer of a three-day ceasefire next week, criticising the reaction so far as ambiguous and historically wrong.

Russia's Foreign Ministry said his comments amounted to a threat, while Dmitry Medvedev, deputy chairman of Russia's Security Council, said nobody could guarantee that the Ukrainian capital of Kyiv would survive to see May 10 if Ukraine attacked Moscow during the May 9 celebrations.