In a stunning declaration of authority, Secretary of Health and Human Services Alex Azar this past week barred the nation’s health agencies, including the Food and Drug Administration, from signing any new rules regarding the nation’s foods, medicines, medical devices and other products, including vaccines.

Going forward, Azar wrote Tuesday in a memorandum obtained by the New York Times, such power “is reserved to the Secretary.” The bulletin was sent to heads of operating and staff divisions within HHS.

It’s unclear if or how the memo would change the vetting and approval process for coronavirus vaccines, three of which are in advanced U.S. clinical trials. Political appointees, under pressure from President Donald Trump, have taken a rash of steps over the past few months to interfere with the standard scientific and regulatory processes at the health agencies. For example, a much criticized guideline on testing for the coronavirus was not written by scientists at the Centers for Disease Control and Prevention, and was posted on the agency’s public website over their objections. It was reversed Friday.

Outside observers were alarmed by the new memo. Dr. Peter Lurie, president of the Center for Science in the Public Interest and a former associate commissioner of the FDA, called it “a power grab.”

Many rules issued by federal health agencies are signed by lawyers or by the heads of agencies, including the FDA, under the umbrella of HHS. The new memo requires the secretary to sign them, which Lurie said could lead to delays in the regulatory process.

“It will introduce an element of inefficiency within government operations that is wholly unnecessary and likely to gum things up,” he said.

Brian Harrison, chief of staff for Azar, described the new policy as “a housekeeping matter,” aimed at no agency in particular. He said it would have no bearing on how the agency deals with virus vaccines.

“This was simply pushing a reset button,” Harrison said. “This is good governance and should have no operational impact.”

HHS has long eyed the rule-making process as ripe for revision. Dr. Scott Gottlieb, who preceded Dr. Stephen Hahn as FDA commissioner, spent much of his nearly two years as head of the agency fending off the new policy, which has been on the conservative agenda for many years. The day before he left office, he added his own signature to a key tobacco and vaping rule that had been signed by a lower-ranking employee to ensure that rule would stay on the books, according to a former senior FDA official.

Although the new memo covers the entire health department, which has 27 agencies and offices, the FDA puts forth far more regulations than other agencies, except for the Centers for Medicare & Medicaid Services, which already requires the secretary’s signature on new rules.

An FDA official, who was not permitted to speak on the record, said the agency was still deciphering what Azar’s memo would mean for their work.

But former senior officials with the FDA and HHS speculated that the intent was to remove rule-making power from Hahn, the FDA commissioner, and to send a signal to Trump that no surprises would come from the agency in the weeks before the election.

“I can only conclude that this memorandum shows a lack of trust in the FDA commissioner and other HHS leaders,” said William Schultz, a former general counsel with HHS and a partner at Zuckerman Spaeder, a law firm.