Biden Officials Say the Truth About Havana Syndrome Is Still Unknown

White House officials said on Friday that the truth behind the mysterious ailments known as Havana Syndrome was still unknown, contradicting a new intelligence assessment about what had befallen spies and diplomats for the last nine years.

On Friday, the Office of the Director of National Intelligence released an updated assessment about the ailments, one that largely reinforced its earlier conclusion that no foreign government was responsible for them. But the document, an update of the intelligence community’s conclusions in 2023, noted that two spy agencies had, at least subtly, shifted their positions.

The White House noted that shift in a briefing with reporters, while the Office of the Director of National Intelligence gave a separate briefing that differed sharply in emphasis and tone.

It was a profoundly odd note for the end of President Biden’s term. While President-elect Donald J. Trump regularly questioned spy agency findings during his first term, Mr. Biden’s White House has embraced the analytic work of its intelligence community. But on Friday, administration officials took a tack far different from that of their intelligence agencies.

The incidents and symptoms were first reported in Cuba in 2016 and were collectively referred to as Havana Syndrome. The ailments, which the government called Anomalous Health Incidents, or A.H.I.s, continued through the Trump administration and reached a high point in the first year of the Biden administration.

Spies and diplomats around the world reported hearing a noise or feeling a change in pressure before suffering from a range of symptoms, including migraines, dizziness and nausea. Some symptoms have continued for years and resembled those associated with traumatic brain injuries.