(Bloomberg) -- China accused the U.S. military of operating “dangerous” biolabs in Ukraine, echoing a Russian conspiracy theory that Western officials warned could be part of an effort to retroactively justify President Vladimir Putin’s invasion. 

“U.S. biolabs in Ukraine have indeed attracted much attention recently,” Chinese Foreign Ministry spokesman Zhao Lijian said Tuesday in response to a question from a local reporter, adding that “all dangerous pathogens in Ukraine must be stored in these labs and all research activities are led by the U.S. side.”

He called on “relevant sides to ensure the safety of these labs” and said “the U.S., as the party that knows the labs the best, should disclose specific information as soon as possible, including which viruses are stored and what research has been conducted.”

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The comments mirror the diversion tactics China’s diplomats used last year when questioned about the origins of Covid-19. Back then they frequently pointed to Fort Detrick, a U.S. military facility in Maryland that the Soviet Union falsely claimed in the 1980s was the source of the virus causing Aids and that Zhao again referenced Tuesday.

Britain’s Defense Ministry said in a Tweet on Tuesday that it had noticed an up-tick in allegations by Russia that Ukraine is working on biological or nuclear weapons. “These narratives are long standing but are currently likely being amplified as part of a retrospective justification for Russia’s invasion of Ukraine,” it added.

Since 1991, a unit of the Department of Defense has cooperated with former satellites of the Soviet Union, including Ukraine, to secure and take apart weapons of mass destruction that have been left behind.

The Nunn-Lugar Cooperative Threat Reduction Program is intended to “support defense and military cooperation with the objective of preventing proliferation,” according to U.S. non-profit organization the Center for Arms Control and Non-Proliferation.

China has walked a fine diplomatic line since Russia attacked Ukraine. It has in recent years been making the case that as a richer, more powerful nation it deserves a bigger say on the world stage. Yet it also wants the benefits of closer ties with Moscow, largely to offset what it sees as Washington’s undue influence.

Zhao repeated at the press briefing that China’s position on Ukraine remains “consistent and clear cut,” signaling that the Asian nation is still trying to avoid picking a side on the issue.

When asked whether China was ready to say that Russia had “invaded” its Eastern European neighbor, Zhao said: “I don’t think the question is of any point.”

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