Tulsi Gabbard, the director of national intelligence, revoked two Biden-era intelligence assessments that cast doubt on the idea that the mysterious ailments known as Havana syndrome that American spies and diplomats had reported were caused by a foreign adversary, officials announced on Thursday.
In a memo, Ms Gabbard said the earlier assessments had improperly excluded evidence, suppressed alternative analyses and relied on an ethically flawed medical study.
Ms. Gabbard’s actions were immediately hailed by former officials who have suffered from the ailments, but it is not clear whether the action will open up a new wide-ranging inquiry.
Representative Rick Crawford, the Arkansas Republican who leads the House Intelligence Committee, had long called on Ms. Gabbard to recall the earlier work.
“The assessment was deliberately manufactured and used to discredit some of our nation’s bravest and impede their access to medical care,” Mr. Crawford wrote.
Havana syndrome, which the government called anomalous health incidents, is a diverse range of symptoms including headaches, dizziness and balance problems. Many patients said the symptoms began after they heard a strange sound and felt intense pressure in their heads.
Ms. Gabbard is expected to step down as the director of national intelligence at the end of next week, which means that the revocation of the assessments was probably one of her final acts but that she will not be in place to supervise further investigations of what may have caused the ailments.
Top intelligence officials in the Biden administration came into office believing that the mysterious ailments were probably the work of Russia or another adversarial power. But after a lengthy inquiry failed to produce intercepts of Russian officers discussing any sort of weapon or device, intelligence officers began to look more skeptically.
A series of intelligence assessments determined that a foreign adversary was “very unlikely” to be responsible for the ailments and questioned that a microwave device or directed-energy weapon was the cause.
Officials briefed on the intelligence work said there were various causes for the symptoms, from undiagnosed conditions to environmental factors to the stress of working for the C.I.A.
Former officials affected by the ailments rejected those explanations. And others in the Biden administration remained unconvinced. White House officials said at the end of the administration that the truth was still unknown.
Ms. Gabbard’s actions this week opened up the possibility that the Trump administration would take a new look at the evidence that Russia or another power could be behind the mysterious episodes.
Marc Polymeropoulos, a former senior C.I.A. officer who suffered Havana syndrome symptoms while in Russia, said that the ailments were caused by a foreign adversary targeting American officials overseas and that the intelligence assessments disputing that were flawed.
“This has been a fight for the truth that many of us have been engaged in for almost a decade,” he said. “It is high time that the government finally came clean on accountability.”
