WASHINGTON (AP) -- Barely a week after mass firings at the Food and Drug Administration, some probationary staffers received unexpected news over the weekend: The government wants them back.

Beginning Friday night, FDA employees overseeing medical devices and other key areas received calls and emails notifying them that their recent terminations had been "rescinded effective immediately," according to messages viewed by The Associated Press.

Three FDA staffers impacted by the decisions spoke with the AP on condition of anonymity because they planned to continue working for the agency and weren't authorized to discuss its internal procedures.

The reversal is the latest example of President Donald Trump and billionaire Elon Musk's chaotic approach to cost-cutting, which has resulted in several agencies firing, and then scrambling to rehire, employees responsible for nuclear weapons, national parks and other government services.

The FDA reinstatements followed pushback by lobbyists for the medical device industry, which pays the agency hundreds of millions of dollars annually to hire extra scientists to promptly review products. The industry's leading trade group said Monday "a sizeable number" of device reviewers would apparently be returning to FDA.

"This would be welcome news, and I appreciate the administration for acting quickly," AdvaMed CEO Scott Whitaker said in an emailed statement. "We all share the same goal -- an efficient, effective FDA review process that helps advance the medical technologies American patients depend on."

FDA staffers said entire teams of five or more medical device reviewers had been reinstated. There did not appear to be a similar effort to rehire staffers in other parts of the agency, including its food and tobacco centers.

The agency hasn't released official numbers on the terminations, but former FDA officials have pegged the number at roughly 700, with more than 220 coming from the medical device center. That would represent roughly 10% of the program's total staffing.

The FDA did not respond to requests Monday about how many employees were being reinstated.

Like other agencies, the FDA terminations went to employees in their probationary period, typically the first two years of federal employment. But that approach resulted in the terminations across key areas where the agency has been working to beef up staffing, including rapidly evolving fields like artificial intelligence and digital health. The cuts also included agency leaders who were recently hired for senior roles.

"The disarray caused by the wholesale termination of a wide swath of device center staff was counterproductive and appears to have caused a variety of unintended and negative results," said Steve Silverman, a former FDA device official who now runs a consulting firm. "It's encouraging to see a shift in the opposite direction that recognizes the critical expertise of these staffers."

Many reviewers have advanced degrees in specialized medical and technological fields. They can typically earn more in the private sector than in government.

Last week, the lobbying group AdvaMed pushed back on the firings, calling on Health Secretary Robert F. Kennedy Jr. to reverse course. The group warned that the cuts would result in slower approvals for companies and fewer new treatment options for patients.

"FDA will lose hundreds of new employees, the best and most innovative hires under our most recent agreement," Whitaker wrote in a statement posted online. He noted that the hiring of FDA device reviewers is largely financed through an ongoing five-year agreement between the FDA and medical device companies.

More than half the device program's $791 million budget last year came from industry fees, according to federal figures. In return, the FDA is obligated to meet certain benchmarks for quickly and predictably reviewing applications for new and updated devices.

FDA staffers who were reinstated said their immediate supervisors received no explanation or advance notice on the decisions. Instead, staffers received calls or emails from the FDA's "Office of Talent Solutions," informing them that their access to FDA computer systems and offices had been restored.

"We are so grateful to still have you working for the FDA and serving the American public!" the emails concluded.

A week earlier, the same employees received emails stating that they were "not fit for continued employment because your ability, knowledge and skills do not fit the agency's current needs."

Nearly half the FDA's budget, or about $3.3 billion, comes from fees paid by drugmakers, device and tobacco companies. The result is that broad cuts to those programs won't add much toward Musk's stated goal of shrinking the federal budget.

But the financial support of industry fees did not appear to help staffers in other parts of the agency.

The agency's tobacco center -- which reviews new products like electronic cigarettes and nicotine pouches -- is 100% funded by industry fees. But there did not appear to be an effort to rehire any of the estimated 100 or so employees fired from that center.

Similarly, the recalls did not appear to apply to the agency's food program, which recently went though a major restructuring to better oversee essential products like infant formula and baby food.

Last week, the FDA's deputy commissioner for foods, Jim Jones resigned, citing "the indiscriminate firing" of nearly 90 staffers in his division, according to a copy of his resignation letter obtained by the AP. The employees fired included those with "highly technical expertise in nutrition, infant formula, food safety response" and chemical safety, Jones said.

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AP Health Writer JoNel Aleccia contributed to this story.

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