China has pushed unfounded Russian allegations that the US is supporting a bio-weapons programme in Ukraine.
On Wednesday, the Russian foreign ministry claimed to have evidence the US was operating biowarfare labs and developing weapons including the plague, cholera and anthrax.
Both Kyiv and Washington have firmly denied the claims, with them US branding them "preposterous" and "classic Russian propaganda".
Instead, the US fears that Russia is “setting the scene” to use chemical weapons of its own and then try to blame Ukraine in a "false-flag attack".
However, the claims coming out of Moscow have since been parroted by Beijing, with Chinese Foreign Ministry spokesman Zhao Lijian saying: “US biolabs in Ukraine have indeed attracted much attention recently".
He added that “all dangerous pathogens in Ukraine must be stored in these labs and all research activities are led by the US side."
Zhao did not provide evidence to back up the claim.
White House press secretary Jen Psaki said that Russia had been making “false claims about alleged US biological weapons labs and chemical weapons development in Ukraine.
“Now that Russia has made these false claims, and China has seemingly endorsed this propaganda, we should all be on the lookout for Russia to possibly use chemical or biological weapons in Ukraine, or to create a false flag operation using them,” she tweeted.
It comes after China accused Nato of pushing tensions between Russia and Ukraine to a "breaking point" - potentially marking a strengthening in the rhetoric stemming from Beijing since the start of the conflict when China refused to condemn Russia's actions.
Xi Jingping has refused to call Putin's actions an "invasion", instead asking Western nations to respect Russia's "legitimate security concerns".
It has called for a solution to the crisis through peaceful negotiations.
At a daily news briefing, Zhao urged the United States to take China's concerns seriously and avoid undermining its rights or interests in handling the Ukraine issue and ties with Russia.
The Chinese Red Cross will also provide a batch of humanitarian assistance worth 5 million yuan (£600K) to Ukraine, consisting of daily necessities.
China sat on the fence as the invasion unfurled, last week opting to abstain in a key vote during an emergency UN general assembly which voted overwhelmingly for a resolution deploring Russia's invasion of Ukraine and called for the immediate withdrawal of its forces.
Vladimir Putin ordered his troops in to invade 15 days ago, causing the biggest humanitarian crisis since World War Two as more than 2 million refugees flee Ukraine for neighbouring countries.
Many Ukrainian cities have since been besieged, with the southern city of Mariupol being cut off from food, water, electricity and vital medicines.
Deputy mayor Sergei Orlov said 17 others had been injured in the attack, including pregnant women.
He told the BBC: "I'm absolutely sure they know about this facility and this is their third hospital that they are destroying in this city.
"I'm absolutely sure (these are their) targets."
Russia has denied allegations of attacking the hospital, with first deputy permanent representative to the United Nations, Dmitry Polyanskiy, claiming the reports were "fake news".