White House officials said Friday that the truth behind the mysterious illnesses known as Havana syndrome is still unknown, contradicting a new intelligence assessment of what has befallen spies and diplomats over the past nine years.

On Friday, the Office of the Director of National Intelligence published an updated assessment on diseaseswhich largely confirmed his earlier conclusion that no foreign government was responsible for them. But the document, an 2023 Intelligence Community Conclusions Updatehe noted that the two spy agencies had, at least subtly, shifted their positions.

The White House noted the change in a press briefing, while the Office of the Director of National Intelligence held a separate briefing that differed sharply in emphasis and tone.

It was an extremely strange note for the end of President Biden’s term. While President-elect Donald J. Trump regularly questioned the spy agency’s findings during his first term, Mr. Biden’s White House embraced the analytical work of its intelligence community. But on Friday, administration officials took an approach markedly different from that of their intelligence agencies.

The incidents and symptoms were first reported in Cuba in 2016 and are collectively called Havana Syndrome. The illnesses, which the government has dubbed Anomalous Health Incidents, or AHI, have continued throughout the Trump administration and peaked in the first year of the Biden administration.

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

A senior administration official, who spoke on condition of anonymity to discuss sensitive material, said the bottom line is that the mystery remains, noting that the government must be open to the fact that “we don’t have all the answers.”

Administration officials have emphasized that some agencies now disagree with the intelligence community’s overall conclusions. Sean Savett, a spokesman for the National Security Council, said the new assessment “involves a change in key judgments by some intelligence components” and reinforces the importance of continuing to research and investigate the issue.

But an official from the Office of the Director of National Intelligence, who spoke on condition of anonymity to discuss sensitive material, said the general conclusion of most agencies remained unchanged. They believe it is “highly unlikely” that a foreign adversary is responsible for the illnesses.

An intelligence official said sensitive intelligence, not a lack of evidence, led several agencies to that conclusion.

Officials previously said no communications or other information indicated that Russia, China, Cuba or any other adversary orchestrated the attacks. Some intelligence indicates that foreign operatives were confused by the accusations of Havana syndrome.

The two agencies that have changed their stance still believe it is unlikely that a foreign government is responsible. But they kept open the possibility that a foreign government had developed a new weapon or prototype to harm US government personnel, although one of the agencies found it unlikely that such a device was used.

Some people suffering from Havana syndrome and their legal representatives criticized the conclusion of the new intelligence report and praised the White House for pushing for a renewed investigation.

Mark Zaid, a lawyer representing several people suffering from Havana syndrome, said intelligence agencies continue to “hide the truth”.

“That the White House’s statement diverges from that of the intelligence community, an entity said to be controlled by the president, speaks volumes for the lack of integrity of the evidence on which to base any conclusion that a foreign government was not involved in AHI attacks on Americans,” Mr. Zaid said. .

Mark Lenzi, a State Department official who developed symptoms while serving in China and continues to be treated for Havana syndrome, said he believes pulsed microwave radiation, a type of directed energy device or weapon that can cause brain injuries, is responsible for the illnesses.

“The White House is absolutely right to be skeptical and reject this biased and invisible false assessment,” said Mr. Lenses.