Satellite images show major expansion at Russian site with secret bioweapons past

Satellite imagery shows construction vehicles renovating the old Soviet-era laboratory and breaking ground on 10 new buildings.

The site, called Sergiev Posad-6, had been quiet for decades , but it had a notorious Cold War past.

It had a history of experiments with the viruses that cause smallpox, Ebola and hemorrhagic fevers.

There has been no sign such weapons have been used in the Ukraine conflict, but the construction of new labs is being closely watched.

The new campus has several hallmarks of a Russian high-security site that are consistent with the precautions taken at a BSL-4 facility.

The security perimeter was cleared of trees to maintain clear lines of sight, experts say.

The Soviet Union used a similar playbook in justifying a massive bioweapons program in the 1970s and 1980s .

The research center was created by the Red Army in the 1950s as one of the Soviet Union’s “closed” military cities.

Up to 6,000 scientists and family members lived inside the walls, in government-built apartment complexes with playgrounds and at least one school.

It is one of only three Russian weapons facilities that never granted access to international experts during the 1990s .