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.

The mass firing of workers at federal health agencies is underway. Thousands of jobs are being cut within the Department of Health and Human Services, the Food and Drug Administration, the National Institutes of Health and the Centers for Disease Control and Prevention.

Larry Summers, who served as Treasury Secretary under Bill Clinton and as director of the National Economic Council in the Obama Administration, took to X, the social media platform formerly known as Twitter,

Summers, who is also the Harvard president, has sharply criticized Donald Trump’s newly announced tariffs, calling them “the most expensive and masochistic” policies the US has pursued in decades.