"Directed" radio frequency is the most plausible explanation for mysterious symptoms experienced by diplomats stationed in U.S. embassies in Havana and elsewhere, a U.S. government report said on Saturday.
The symptoms appear "to be consistent with the effects of directed, pulsed radio frequency energy," said the report by the National Academies of Sciences, Engineering.
Diplomats in some postings have been plagued with nausea, headache, dizziness and other unexplained symptoms. This "Havana syndrome" has long been the subject of intense speculation, given the nature of the symptoms, the location of the postings, and the silence of the US government.
Saturday's report marks the first time Washington has officially offered an explanation, although inconclusive.