MOSCOW - The Russian Defense Ministry said Thursday that US-funded biological laboratories in Ukraine worked on establishing a mechanism "for the covert transmission of deadly pathogens".

Experts of the Russian Nuclear, Biological and Chemical Protection Troops found evidence that bio-materials taken in Ukraine were transferred to foreign countries, as instructed by the United States, the ministry said.

A US project, which was carried out in Ukraine, studied the transfer of pathogens "by wild birds migrating between Ukraine and Russia and other neighboring countries", the ministry said.

"According to the documents, the US side planned to organize work on pathogens of birds, bats and reptiles in Ukraine in 2022," the ministry said, adding that America was studying how they could further transfer the African swine fever and anthrax.

Experiments with samples of coronaviruses found in bats were also carried out in biological laboratories that were created and funded in Ukraine, it added.

The ministry said it will show another set of documents received from Ukrainian employees of the biological laboratories and present the results of assessment in the near future.

On Tuesday, US Undersecretary of State for Political Affairs Victoria Nuland testified before a Senate Foreign Relations Committee hearing on Ukraine, admitting "Ukraine has biological research facilities".

"We are working with the Ukrainians on how they can prevent any of those research materials from falling into the hands of Russian forces should they approach," she said.