The White House on Wednesday said Russia's claims about alleged US involvement in biological weapons labs and chemical weapons development in Ukraine were false.
"We took note of Russia’s false claims about alleged US biological weapons labs and chemical weapons development in Ukraine," White House press secretary Jen Psaki said in a series of tweets.
She said Russia could possibly be laying the groundwork for use of chemical or biological weapons in Ukraine "or to create a false flag operation using them" but did not offer evidence.