The head of the U.S. intelligence community said Thursday that biolabs in Ukraine do not produce weapons or conduct dangerous research, slamming claims to the contrary as "classic" Russian propaganda.

Director of National Intelligence Avril Haines told the Senate Intelligence Committee that Ukraine "operates a little over a dozen" biolabs for biodefense and public health response. She said the U.S. has, at least in the past, "provided assistance" to the labs "in the context of biosafety."

"Which is something we have done with a variety of different countries," she added.

Haines emphasized that the labs are not being used for any type of weapon development.

"We do not assess that Ukraine is pursuing either biological weapons or nuclear weapons," Haines said. "This influence campaign is consistent with long-standing Russian efforts to accuse the United States of sponsoring bioweapons. ... This is a classic move by the Russians."

The Biden administration, Ukrainian officials and outside experts have said Russia is pushing propaganda and a disinformation campaign around chemical and biological weapons in Ukraine as a pretext for a potential attack, and potentially one that the Russians could carry out.

CIA Director William Burns on Thursday said that Russia’s accusations of chemical weapons “is very much a part of Russia’s playbook. They’ve used those weapons against their own citizens, they’ve at least encouraged the use in Syria and elsewhere; so it’s something we take very seriously.” 

White House press secretary Jen Psaki has called Russia's claims "false" and "preposterous."

"It’s the kind of disinformation operation we’ve seen repeatedly from the Russians over the years in Ukraine and in other countries, which have been debunked, and an example of the types of false pretexts we have been warning the Russians would invent," she said in a statement Wednesday.

Sen. Marco Rubio (R-Fla.), the vice chair of the Senate Intelligence Committee, said Thursday that Russia has been "laying out" the idea that the U.S. has harbored bioweapons at labs in Ukraine for months.

During the hearing, Rubio pressed Haines on if there was, if not a weapon, some type of pathogen or tool the Russians could wield in the war against Ukraine or as part of its disinformation campaign. 

The senator explained that because of the COVID-19 pandemic, the American public was worried about why U.S. officials were so concerned with Russians seizing the labs.

"We're all coming off the trauma of COVID-19, the possibility that there might have been an accident or a leak out of a lab there that we still don't have an answer to," Rubio said. "It's really important for this effort to understand what exactly is in these labs that we are so worried about."

Haines reiterated that the labs work on research to help address viruses that could cause pandemics and other health concerns, but cited concerns about Russians potentially misusing lab equipment or pathogens.

"We have to be concerned in the same way we have to be concerned with the nuclear power plant or other facilities [if] they are seized," Haines said. "There may be damage done or theft and they may in fact misuse some of the material that's there that is not intended for weapon purposes but nevertheless could be used in dangerous ways."

The Biden administration has warned that Russia's bioweapon claims could lead to the deployment of chemical weapons in Ukraine as Russian forces try to overcome fierce resistance from Ukrainian troops, heading into the second week of the invasion.

Burns said baseless claims floated about biolabs could be a "false flag operation" designed to accuse Ukrainians of using bioweapons in an attempt to give Russian forces a pretext to use a bioweapon themselves.

"That should give us all pretty serious concern about their propaganda," Burns said.

— Laura Kelly contributed.