China has issued a call urging "all sides" to ensure the safety of nuclear facilities in Ukraine, reflecting the nation's unease over Russia's shelling of the Zaporizhzhia nuclear plant, Europe's largest.

"We will monitor the situation and call on all sides to exercise restraint, avoid escalation and ensure the safety of relevant nuclear facilities," the Chinese Foreign Ministry said following the overnight attack, which sparked a fire at the Ukrainian compound.

The foreign ministry spokesman, Wang Wenbin, refused to condemn the Russian attack or call it an invasion. That is consistent with the neutral stance that China has adopted on the issue at the recent meetings at the United Nations.

China does not want to be seen as a country condoning any military act that would endanger safety at a nuclear power plant, said a Chinese scholar who did not wish to be identified.

"We have our own technology for nuclear plants, the Hualong One technology, which we have begun to export," he said.

China signed an agreement with Argentina in January to build the Atucha III nuclear power plant at a cost of $8 billion. It will be the second major export of Hualong One technology, a rival to the U.S. Westinghouse technology, after Beijing built a nuclear power plant in Pakistan under the Belt and Road Initiative.

China was among the first to ask the International Atomic Energy Agency to take immediate steps to ensure the safety of nuclear facilities in Ukraine amid the Russian invasion. Ukraine has 15 nuclear reactors at four sites.

"China is concerned about the safety, security and safeguards of nuclear facilities in Ukraine," China's envoy at the IAEA, Wang Qun Wang, was quoted as saying by the Chinese mission in Vienna.

Speaking at the IAEA meeting on Wednesday, the envoy said, "The responsibility for nuclear safety and security rests with sovereign states, and related issues should be handled through established procedures.

"We hope the relevant parties will act cautiously to avoid causing man-made nuclear safety and security incidents," he said. "The IAEA should also take full consideration of the security situation in Ukraine in accordance with its mandate and properly address the issue of security protection in Ukraine."

Russian soldiers earlier took over Ukraine's decommissioned Chernobyl power plant, site of a nuclear accident in 1986, raising fears about the safety of other nuclear facilities in Ukraine.

In another significant move, the China-led Asian Infrastructure Investment Bank has put a hold on its financial plans in Russia and Belarus, a close ally of Moscow. Those plans are now under review.

In a statement, the Beijing-headquartered AIIB said bank management was taking steps to safeguard its financial position in light of the evolving economic and financial situation.

"Under these circumstances, and in the best interests of the bank, management has decided that all activities relating to Russia and Belarus are on hold and under review."