China called for a comprehensive ceasefire in Ukraine on Friday and President Volodymyr Zelenskiy said he was open to considering parts of a 12-point peace plan put forward by Beijing.

On the first anniversary of Russia's invasion of Ukraine, Moscow's ally China urged both sides to agree to a gradual de-escalation, warned against the use of nuclear weapons and said conflict benefited no one.

The plan, set out in a foreign ministry paper, was largely a reiteration of China's line since Russia launched what it calls its "special military operation" on 24 Feb last year.

China has refrained from condemning its ally Russia or referring to Moscow's intervention in its neighbour as an "invasion". It has also criticised Western sanctions on Russia.

"All parties must stay rational and exercise restraint, avoid fanning the flames and aggravating tensions, and prevent the crisis from deteriorating further or even spiralling out of control," the ministry said in its paper.

The initial reaction from Kyiv was dismissive, with a senior adviser to President Zelenskiy saying any plan to end the war must involve the withdrawal of Russian troops to borders in place when the Soviet Union collapsed in 1991.

However, Zelenskiy himself struck a more receptive tone in a news conference to mark the first anniversary of the conflict.

Russia said it appreciated China's plan and that it was open to achieving its goals through political and diplomatic means.

The proposals however cut little ice with NATO.

"China doesn't have much credibility because they have not been able to condemn the illegal invasion of Ukraine," NATO Secretary-General Jens Stoltenberg told reporters in Tallinn.

'NO NUCLEAR WAR'

Russian President Vladimir Putin has signalled he will double down on the conflict, despite major battlefield defeats in the past year, and has raised the spectre of nuclear weapons.

China said nuclear weapons must be avoided.

"Nuclear weapons must not be used and nuclear wars must not be fought," the foreign ministry said. "We oppose development, use of biological and chemical weapons by any country under any circumstances."

Since the war began weeks after Beijing and Moscow announced a "no limits" partnership, President Xi Jinping has spoken regularly with Putin but not once with his Ukrainian counterpart Zelenskiy. China's top diplomat Wang Yi visited Moscow for talks this week.

Brazil's new President Luiz Inacio Lula da Silva stressed the need for a peace deal brokered by outsiders.

"It is urgent that a group of countries not involved in the conflict assume the responsibility of leading negotiations to reestablish peace," Lula said on Twitter.

There had been speculation that President Xi would deliver a "peace speech" on Friday but that did not occur.