Russian leader Vladimir Putin could unleash a deadly biological weapon on Ukraine and blame the US, the former head of the British Army's chemical weapons unit has warned.
It comes as scientists in Ukraine have been told to destroy all "high-threat" lab diseases.
Colonel Hamish de Bretton-Gordon, former chief of the British Army's chemical weapons unit, said Russian troops could storm a lab and use it as a base to unleash a bioweapon.
He also warned Putin's "indiscriminate" bombing campaign could hit a lab.
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The World Health Organisation has said the most deadly pathogens in Ukraine's labs should be wiped out amid fears of "potential spills" caused by Putin's relentless bombing.
Russian forces have already seized control of Chernobyl and Zaporizhzhia - two of the largest nuclear power plants in Ukraine.
It is thought there are more than 4,000 labs in Ukraine and although they do not have a level-four lab, which handles the world's most dangerous pathogens - two do have clearance to work with high-level pathogens.
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The level-three lab works with coronaviruses, tuberculosis, yellow fever, SARS, West Nile, and some strains of influenza.
One of the two labs is in Odessa and the other is in Kyiv.
Colonel de Bretton-Gordon said Putin could unleash a bioweapon "more lethal than Covid".
He told The Sun Online : "The Russians could use a Ukrainian lab to release a bioweapon.
"It would be ideal - they could blame the US and Ukraine for the release of the pathogen.
"The chance to go into a lab would be gold dust for the Russians.
"They could use it in their own disinformation campaign - they would use it for propaganda."
If Putin succeded in blaming the US it could be used as a justification to escalate his war effort.
Mr Bretton-Gordon also said that the "reckless" bombing by the Russians could spark a lab accident.
He added: "If a massive bomb hit the lab, the pathogens could be released - but it's more likely they would be destroyed."
It comes as NATO Secretary-General Jens Stoltenberg has warned Russia might use chemical weapons following its invasion of Ukraine.
"In recent days, we have heard absurd claims about chemical and biological weapons laboratories," Stoltenberg was quoted by Welt am Sonntag as saying, adding that the Kremlin was inventing false pretexts to justify what could not be justified.
"Now that these false claims have been made, we must remain vigilant because it is possible that Russia itself could plan chemical weapons operations under this fabrication of lies. That would be a war crime," Stoltenberg was quoted as saying.
He added that although the Ukrainian people were resisting the Russian invasion with courage, the coming days are likely to bring even greater hardship.
