The CIA has removed its top officer in Vienna following criticism of his management, including what some considered an insufficient response to a growing number of mysterious health incidents at the U.S. Embassy there, according to current and former U.S. officials.

The sidelining of the station chief in one of the largest and most prestigious CIA posts is expected to send a message that top agency leaders must take seriously any reports of “Havana Syndrome,” the phenomenon named after the Cuban capital where U.S. diplomats and intelligence officers had first reported unusual and varied symptoms, from headaches to vision problems and dizziness to brain injuries, that started in 2016.

In recent months, the Austrian capital has become a hotbed of what the CIA officially calls “anomalous health incidents.” The ouster of the CIA station chief comes as the State Department’s top official overseeing Havana Syndrome cases leaves her position after six months.

The department said Ambassador Pamela Spratlen was exiting because she had “reached the threshold of hours of labor” permitted under her status as a retiree. But she faced calls for her resignation after a teleconference with victims who had asked a question about an FBI study that determined the illnesses had a psychological origin rather than a physical one.

Spratlen declined to say if she believed the FBI study was accurate or not, angering victims who believe their symptoms are the result of an attack, possibly with microwaves or some form of directed energy. NBC News first reported the exchange. The FBI declined to comment.

Dozens of U.S. personnel in Vienna, including diplomats and intelligence officials, as well as some of the children of U.S. employees, have reported symptoms, according to the current and former officials who spoke on the condition of anonymity to discuss a sensitive matter.

Intelligence experts said that if the syndrome is the result of a deliberate attack, targeting the children and family members of U.S. diplomats and spies would mark a dramatic escalation. As a result of the incidents in Vienna, offices within the U.S. mission there were shut down last month, impairing embassy functions, one U.S. official said.

The removal of the station chief, the illnesses among children and the closure of embassy offices have not been previously reported. When asked about embassy operations in Vienna, a State Department spokesperson said, “We don’t discuss embassy operations or specific reports, but we take each report we receive extremely seriously and are working to ensure that affected employees get the care and support they need.”

CIA Director William J. Burns has publicly described the incidents as “attacks,” and some U.S. officials suspect they are the work of Russian operatives. Other officials have attributed them to a psychogenic illness experienced by individuals working in a high-stress environment. Despite four years of investigations across multiple administrations, the U.S. government has so far been unable to determine a cause.

The CIA station chief had come under criticism for not taking swifter action in response to symptoms reported among intelligence personnel, said U.S. officials. People familiar with his performance described him as skeptical that the illness was genuine and insensitive to the suffering of the staff he led. Attempts to reach the station chief were unsuccessful.

There have been more cases of illness reported in Vienna than in any other city except Havana. The station chief’s response to the health problems wasn’t the only factor in his dismissal, but his recall has sent a signal through the U.S. intelligence community how seriously Burns takes protecting U.S. personnel and getting to the bottom of the mysterious incidents, current and former government officials said.

In July, Burns placed a senior CIA officer who played a leading role in the hunt for Osama bin Laden in charge of the task force investigating the cause of the illnesses. When asked about the removal of the station chief, a CIA spokesperson declined to comment on the specific matter.

“Director Burns has made it a top priority to ensure officers get the care they need and that we get to the bottom of this,” the spokesperson said. “He has made changes in our Office of Medical Services from his first day on the job six months ago, elevating a doctor focused on patient care to lead our efforts caring for affected individuals, and also tripled the number of medical staff focused on” anomalous health incidents.

Senior officers from the CIA and the Office of the Director of National Intelligence are also leading a panel of experts from government and the private sector to investigate the possible causes of the incidents.

In a recent call to affected State Department employees, Secretary of State Antony Blinken said he places a high priority on the issue and will work to keep the workforce informed about efforts to address the incidents.

As lawmakers pressure the administration to address the phenomenon, the National Security Council has sought to encourage employees across the federal government to report any potential health issues that they may be experiencing. An increase in reported health incidents has ensued. In some cases, U.S. employees have reported that they experienced some symptoms related to Havana Syndrome but upon further diagnosis the ailments were attributed to other factors, said a senior administration official.

As the mystery of what’s behind the attacks has deepened, the number and severity of incidents has grown. An intelligence officer traveling with Burns in India earlier this month reported symptoms of Havana Syndrome and required medical attention, current and former officials said.

Some saw that incident, first reported by CNN, as a message to CIA leaders that they too can be targeted anywhere. Yet there is no clear pattern to the health events, roughly 200 of which have been reported around the world in the past five years, on every continent except Antarctica.

In public remarks last week, David Cohen, the CIA’s deputy director, said the agency was trying to attribute the source of the incidents. “In terms of have we gotten closer, I think the answer is yes, but not close enough to make analytic judgment that people are waiting for,” Cohen said.

Last month, two U.S. personnel in Hanoi reported symptoms just before the arrival of Vice President Harris, and that delayed her visit to the Vietnamese capital by a few hours. Other cases have been reported in Russia, China, Colombia, Uzbekistan and the United States.

This week, the House of Representatives unanimously passed legislation that would provide funding for treatment and aid to individuals who may have been affected by Havana Syndrome. The Senate passed the bill in June, and it heads to President Biden for his expected signature.

Marc Polymeropoulos, a former CIA officer forced to retire early while suffering symptoms, including painful headaches, after a trip to Moscow in 2017, has called the passage of the legislation a “watershed moment for victims” because it has marked a “fundamental admission by the U.S. government that the attacks that continue to this day are real.”

“No longer can the U.S. government claim we were all making it up, which they did for so long and caused not only psychological injury but also delayed medical care, which compounded our injuries,” he said. The bill would also help compensate personnel who paid for medical treatments out of their own pocket and who were compelled to retire early.

Burns has met privately with several officers who believe they were injured and has told them their care is a priority. He has also visited Walter Reed National Military Medical Center, where some have been diagnosed with brain injuries and are receiving specialized medical treatment.

But the Biden administration is left with few clear options how to respond to the events. Some officials have speculated that several countries could be using energy weapons to sicken U.S. personnel, arguing that the focus on Russia might be too narrow. Others have noted that there is scant evidence connecting the use of energy weapons to the symptoms reported.