Intelligence chief: 'Havana syndrome' likely not caused by foreign foe

March 1 (UPI) -- The mysterious "Havana syndrome," a set of medical symptoms suffered by U.S. diplomats and military personnel overseas, is "very unlikely" caused by a foreign foe, the Office of the Director of National Intelligence said Wednesday.

The unusual diagnoses, with some of the first cases identified by U.S. officials in Havana in 2016, have resulted in unknown reasons for symptoms ranging from ringing in the ears to cognitive difficulties.

Director of National Intelligence Avril Haines said the events, which are formally known as anomalous health incidents, were likely caused by other factors such as "pre-existing conditions, conventional illnesses and environmental factors."

In January 2022, the CIA concluded that the Havana syndrome was unlikely caused by a foreign adversary. The CIA said then it believed the mysterious ailments were probably created by environmental causes, undiagnosed medical conditions or stress.

Some in Congress have argued that Havana syndrome could be a targeting effort by Russia against U.S. personnel, but investigators through the years have discovered no significant evidence supporting that possibility.

The U.S. intelligence community said it has reviewed hundreds of incidents and a wide range of factors surrounding them but failed to come up with any definitive answers. About 1,500 suspected cases have been reported by the U.S. government in 96 countries.

People who report suffering from the ailments have criticized the U.S. government as not taking them seriously enough.