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Russia and China are doubling down on claims that the United States is conducting biological weapons research in "biolabs" across war-torn Ukraine – assertions that leaders in Washington and Kyiv have called absurd.

Russian diplomat Dmitry Polyanski has requested the United Nations Security Council discuss the alleged research at a meeting Friday, the Kremlin-aligned media outlet RIA Novosti reported earlier.

The report also highlighted allegations from Russia’s Defense Ministry that claim the U.S. spent $200 million on Ukrainian labs for a purported "bioweapons program." Russia claims its troops uncovered evidence during Vladimir Putin’s invasion of Ukraine, which he calls a "special military operation."

"This is exactly the kind of false flag effort we have warned Russia might initiate to justify a biological or chemical weapons attack," Olivia Dalton, a spokesperson for the U.S. Mission to the United Nations, told Fox News Digital Thursday. "Russia has a well-documented history of using chemical weapons and has long maintained a biological weapons program in violation of international law."

Russia also has a track record of accusing Western allies of misconduct it's conducting itself, she said.

"We’re not going to let Russia gaslight the world or use the UN Security Council as a venue for promoting their disinformation.," she added.

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UN Security Council meets after Russia recognized two breakaway regions in eastern Ukraine as independent entities, in New York City

Norwegian Ambassador to the United Nations Mona Juul, Dmitry Polyansky, First Deputy Permanent Representative to the United Nations and Russian Ambassador to the UN Vasily Nebenzya speak as the United Nations Security Council meets after Russia recognized two breakaway regions in eastern Ukraine as independent entities, in New York City, U.S. February 21, 2022.   (REUTERS/Carlo Allegri)

Earlier Thursday, when asked what proof China had of the claims during his daily news briefing, Foreign Ministry spokesman Zhao Ljian provided none but demanded the U.S. answer questions about the issue.

"What has the U.S. been doing at Fort Detrick and its 336 biological laboratories abroad?" he asked. "Do the activities conform to the stipulations of the [Biological and Toxin Weapons Conventions]?"

Fort Detrick is the home of the U.S. Army Medical Research and Development Command in Maryland.

Earlier Thursday, U.S. Defense Department officials said that there were five biological research laboratories in Kyiv – focused on "diagnostics, therapeutics, treatments, prevention and vaccines" – and not on military or biological weapons research.

"There are no DOD bioweapon labs in Ukraine or anywhere else in the world," the officials said.

White House Press Secretary Jen Psaki called the claims of a global network of U.S.-run biological weapons labs "preposterous" Wednesday. She also warned the claims could be an attempt to create cover for a Russian chemical or biological attack on Ukraine, noting that disinformation is part of the Kremlin’s weapons kit.

United Nations Security Council meeting after Russia's invasion of Ukraine, in New York City

FILE PHOTO: A general view of the United Nations Security Council meeting after Russia's invasion of Ukraine, at the United Nations Headquarters in Manhattan, New York City, New York, U.S. February 28, 2022.  (REUTERS/Carlo Allegri/File Photo)

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"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 said. "It’s a clear pattern, and no one should fall for it."

Russia’s UN request follows international calls for the country to have its permanent seat on the Security Council removed.

"Moscow is driving decisions in the United Nations through its role as a Permanent Member of the Security Council," U.S. Sen. Marsha Blackburn, R-Tennessee, said days after Russia’s invasion of Ukraine. "Russia must be exiled from the international community."

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When the Soviet Union collapsed 30 years ago, Russia inherited its seat as one of five permanent fixtures on the UN Security Council. The move went uncontested at the time – but it grants the Kremlin veto power over council decisions.

Moscow used that veto last month when the Security Council floated a resolution denouncing Putin’s invasion of Ukraine and demanding a withdrawal of Russian troops.

Ukrainian President Volodymyr Zelenskyy has also called on the UN to revoke Russia’s Security Council seat.

Ukrainian President Volodymyr Zelenskiy speaks in Kyiv

Ukrainian President Volodymyr Zelenskiy speaks in Kyiv, Ukraine, March 10, 2022, in this still image taken from video.   (Ukrainian Presidential Press Service/via Reuters TV/Handout via REUTERS )

"No chemical or any other weapons of mass destruction were developed on my land," he said in a video posted to Telegram Thursday, translated from Ukrainian. "The whole world knows that."

Undersecretary of State for Political Affairs Victoria Nuland told the Senate Foreign Relations Committee Tuesday that the U.S. was aware of "biological research facilities" in Ukraine under questioning from Sen. Marco Rubio, R-Florida. 

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He asked her if Ukraine has chemical or biological weapons.

"Ukraine has biological research facilities," Nuland replied, "which in fact we are quite concerned Russian troops, Russian forces, may be seeking to gain control of, so we are working with the Ukrainians on how they can prevent any of those research materials from falling into the hands of Russian forces."

She also said that if anyone were to deploy a chemical or biological attack in Ukraine, she "100%" believed it would be the Russians.

Following the collapse of the Soviet Union, the U.S. has led an international effort to secure and dismantle leftover Soviet-era weapons of mass destruction, including in Ukraine. In August 2005, Washington and Kyiv agreed to cooperate to prevent the "proliferation of technology, pathogens and expertise that could be used in the development of biological weapons."

Russia's invasion of Ukraine continues, in the Vyshgorod region near Kyiv

Members of the Ukrainian forces sit on a military vehicle amid Russia's invasion of Ukraine, in the Vyshgorod region near Kyiv, Ukraine March 10, 2022.   (REUTERS/Serhii Nuzhnenko)

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In addition to failing to secure many Soviet weapons in the 1990s, Russia also has a history of violating international laws governing biological and chemical weapons, according to the White House.

Psaki said Wednesday the attempted poisoning of Kremlin-critic Alexey Navalny and Russia’s support of Syrian ruler Bashar al-Assad’s chemical weapons attacks on rebels within his own borders.

Pentagon press secretary John Kirby also addressed the claims Wednesday, saying they were "malarkey" and "classic Russian propaganda."

"We are not developing biological or chemical weapons inside Ukraine," he said. "It's not happening."

Fox News' Adam Sabes contributed to this report.