The Centers for Disease Control and Prevention is going dark, along with other federal agencies within the umbrella of the U.S. Department of Health and Human Services. This week, the returning Trump administration told these agencies to stop talking to the public—for how long, no one knows.

President Donald Trump is pulling the U.S. out of the World Health Organization, raising concerns about the U.N. agency's ability to fight diseases and respond to emergencies around the globe without its biggest funder.

Agencies affected include the U.S. Department of Health and Human Services, U.S. Food and Drug Administration, U.S. Centers for Disease Control and Prevention and National Institutes of Health, the Washington Post reported.

President Trump has imposed temporary freezes at the National Institutes of Health on meetings, travel, communications and hiring, citing the need to review protocols.