CIA says mysterious 'Havana Syndrome' is unlikely to be attack from foreign country, reports say

• US personnel around the world have reported mysterious symptoms of the so-called "Havana Syndrome."
• Theories include microwave weapons, and the CIA has explored the possibility of it being an attack.

The CIA has decided that most cases of the mysterious "Havana Syndrome" that has affected US personnel around the world is unlikely to be the result of a foreign power, The New York Times and NBC News reported.

Hundreds of Americans, including diplomats and officials, across the world have reported mysterious symptoms, including in Cuba, China, Russia, and the US. Symptoms include nausea, headaches, vertigo, and memory loss.

Theories behind it have included pesticides and a microwave weapon aimed by a hostile nation, and US officials previously said that the CIA had warned Russia that it would retaliate if it was found to be responsible.

But the CIA said in an internal assessment that the vast majority of cases were unlikely to be the result of any foreign power because the CIA found other explanations for the symptoms, officials told The Times and NBC News.

Most of the cases can be explained by the effects of the environment, undiagnosed medical conditions or stress, CIA officials told The Times.

But around two dozen cases remain unexplained, and the CIA is still considering that they could be the result of an attack by another country, the reports said.

People who have suffered from the Havana Syndrome symptoms are unhappy with the reports findings, both outlets reported.

The health incidents first emerged among US personnel in Havana, Cuba, in 2016, which is where the illness got its name.