The CIA has determined that most cases of Havana syndrome were not caused by a sustained global campaign by a foreign power against US diplomats and spies, according to a new report.

The majority of 1,000 cases of the mysterious ailment reviewed by US officials show it is unlikely to have been caused by Russia or another foreign adversary, CIA officials told the New York Times about a study’s preliminary findings.

The officials said the symptoms can be explained by environmental causes, undiagnosed medical conditions or stress.

But the CIA is still continuing to investigate some two dozen unexplained cases that may provide clues as to whether a foreign power is responsible for the condition, which has affected US officials and relatives overseas, including in Vienna, Paris, Geneva and Havana, the paper reported, citing agency sources.

In addition to those two dozen cases, a significant number of others are still unexplained, the Times cited a CIA official as saying.  

The CIA did not rule out foreign involvement in those cases.

“In hundreds of other cases of possible symptoms, the agency has found plausible, alternate explanations,” sources told NBC News, which reported that US officials stressed that that interim report was not a final conclusion of the Biden administration or the entire intelligence community.

Havana syndrome — which is referred to by the US government as an “anomalous health incident” — has been linked to suspected radiation attacks that have afflicted hundreds of American spies and diplomats around the globe.

It was first reported among American officials in Cuba’s capital in 2016. Symptoms include migraines, nausea, memory lapses and dizziness. It is sometimes preceded by a piercing sound.

CIA Director William Burns told the Times that the agency was pursuing a complicated issue with “analytic rigor, sound tradecraft and compassion” and stressed that CIA officers had experienced real symptoms.

“While we have reached some significant interim findings, we are not done,” Burns told the Times in a statement. “We will continue the mission to investigate these incidents and provide access to world-class care for those who need it.”

Secretary of State Antony Blinken told MSNBC last week that the US still doesn’t know what Havana syndrome is — and that the entire federal government is working to get to the bottom of the illness.

“To date, we don’t know exactly what’s happened and we don’t know exactly who is responsible,” Blinken said.

He added the US has raised the illnesses with the Russians but still can’t make a determination about who is to blame.

Sources told NBC News that people who have suffered possible Havana syndrome symptoms and have been briefed on the CIA’s assessment have expressed profound disappointment. 

“CIA just kind of struck out on their own,” a person briefed on the findings told NBC.

“Even two dozen cases is a lot of cases if Americans were attacked,” another told the outlet.

Meanwhile, the White House National Security Council has convened a task force including outside medical and scientific experts to study the condition, NBC News reported.

It is expected to release some findings in the near future, officials said.

The Defense Department, the FBI and the State Department also are still investigating the syndrome and how to combat it, officials told the outlet.

With Post wires