A massive wave of job cuts got underway at US health agencies Tuesday, with some employees receiving early-morning emails saying their jobs were eliminated and some unable to access the building when they arrived at work.

The move comes after Secretary Robert F. Kennedy Jr.’s announcement of a sweeping reduction of the Department of Health and Human Services.

Some employees at US health agencies have started receiving notice that their jobs are being cut. “This [reduction in force] action does not reflect directly on your service, performance or conduct,” according to one email to a US Centers for Disease Control and Prevention staff member that was obtained by CNN.

The Trump administration began mass layoffs of 10,000 staffers at U.S. health agencies on Tuesday, according to multiple sources familiar with the situation, with security guards barring entry to some employees just hours after they received dismissal notices.

Switzer Memorial Building in Washington on Tuesday.Credit...Roberto Schmidt/Agence France-Presse — Health job cuts: The Trump administration laid off thousands of federal health workers, dismissing senior leaders and top scientists in a purge that outside experts and former officials said would cause an immeasurable loss of expertise.

Another round of “deferred resignation” offers is part of the Trump administration’s stepped-up effort to rapidly downsize the government.

Health Secretary Robert F Kennedy Jr announced last week that 10,000 employees would be let go, and about a third are expected to be cut from the agency overseeing food and drug safety. Tuesday's layoffs included several top officials within HHS,

The U.S. Senate Health, Education, Labor, and Pensions Committee will on April 10 hold a hearing on the reorganization of the Department of Health and Human Services, its chairman Senator Bill Cassidy said in a statement.