WASHINGTON — The top communications official at the powerful cabinet department in charge of combating the coronavirus made outlandish and false claims on Sunday that career government scientists were engaging in “sedition” in their handling of the pandemic and that left-wing hit squads were preparing for armed insurrection after the election.

Michael Caputo, 58, the assistant secretary of public affairs at the Department of Health and Human Services, said without evidence that the Centers for Disease Control and Prevention was harboring a “resistance unit” determined to undermine President Trump.