Three days after being accused by an international tribunal of war crimes in Ukraine, Russian President Vladimir Putin will be looking more than ever for a show of solidarity from his Chinese counterpart Xi Jinping when he welcomes him to Moscow on Monday.

Xi will be the first world leader to shake Putin's hand since the International Criminal Court (ICC) issued an arrest warrant for the Russian leader on Friday over the deportation of Ukrainian children to Russia since the start of the war.

Russia will present Xi's trip - his first since securing an unprecedented third term this month - as evidence that it has a powerful friend prepared to stand with it against a hostile West that it says is trying in vain to isolate and defeat it.

Neither Moscow nor Beijing are members of the ICC, whose action the Kremlin said was outrageous but legally void. But by making Putin a wanted man in 123 countries virtually on the eve of Xi's trip, the court has shone an awkward spotlight on a meeting that was already delicate for the Chinese leader.

As Russia's army struggles in Ukraine and the United States warns China against supplying Moscow with weapons, Beijing faces a choice it had hoped to avoid, said Jonathan Eyal of the Royal United Services Institute, a London think-tank.

"Either they do nothing and risk seeing Russia humiliated in Ukraine, which is not in China’s interest. Or they come to Russia’s aid and risk a much bigger deterioration in their relationship with the United States and other Western countries," he said in a telephone interview.

In an article for a Chinese newspaper, published on the Kremlin website late on Sunday, Putin said he had high hopes for the visit by his "good old friend" Xi, with whom he signed a "no limits" strategic partnership last year.

He also welcomed China's willingness to mediate in the conflict.

"We are grateful for the balanced line of (China) in connection with the events taking place in Ukraine, for understanding their background and true causes. We welcome China's willingness to play a constructive role in resolving the crisis," Putin said.

China last month published a 12-point paper calling for dialogue and a settlement in Ukraine, but it contained only general statements and no concrete proposal for how the year-long war might end.

Ukraine cautiously welcomed the Chinese proposal but says any settlement would require Russia to withdraw from all the territory it has seized, including the Crimean peninsula it annexed in 2014.

The United States has reacted with extreme scepticism to China's involvement, given its refusal to condemn Russia's invasion.

White House spokesperson John Kirby told Fox News on Sunday that any call by Putin and Xi for a ceasefire now would be unacceptable because it would just "ratify Russia's conquest to date".

"All that's going to do is give Mr Putin more time to re-fit, re-train, re-man, and try for renewed offensives at a time of his choosing," he said.