Doctors and scientists increasingly suspect attacks with unconventional microwave weapons as the cause of the mysterious ailments that have stricken more than three dozen American diplomats and their families in Cuba and China, The New York Times reported Sunday.

The victims reported hearing intense high-pitched sounds in their hotel rooms or homes followed by symptoms that included nausea, severe headaches, fatigue, dizziness, sleep problems and hearing loss.

A medical team that examined 21 of those affected in Cuba did not mention microwave weapons as a cause in a study published in March in the Journal of the American Medical Association.

But its lead author, Douglas Smith, the director of the Center for Brain Injury and Repair at the University of Pennsylvania, told the Times that microwave weapons are now considered a main suspect and that the team is increasingly sure the diplomats suffered brain injury.

"Everybody was relatively skeptical at first," he was quoted as saying, "and everyone now agrees there's something there." Neither the State Department nor the FBI has publicly pointed to microwave weapons as the culprit, and the Times said there were many unanswered questions as to who might have carried out the attacks and why.