Doctors and scientists increasingly suspect that weaponized microwaves were the cause of unexplained noises and illnesses that afflicted U.S. diplomats and their families in Cuba and China in the last year, The New York Times has reported.
The more than three dozen victims reported hearing intense, high-pitched sounds in their homes or hotel rooms, followed by symptoms that included nausea, severe headaches, fatigue, dizziness, sleep problems, and hearing loss.
While a medical study of 21 Cuba victims published in March did not mention microwave weapons as a cause, its lead author told the Times on September 1 that microwave weapons were now considered a primary suspect and that his investigative team was increasingly certain the diplomats suffered brain injury.
"Everybody was relatively skeptical at first...and everyone now agrees there's something there," Douglas Smith, the director of the Center for Brain Injury and Repair at the University of Pennsylvania, told the Times.
Neither the U.S. State Department nor the FBI has publicly blamed microwave weapons for the illnesses. The Times said it is still a mystery who might have carried out the microwave attacks and why.
Speculation among scientists has centered on the possibility that pro-Russian dissidents in Cuba might have used weaponized microwaves to try to thwart a warming of ties between Washington and Havana that occurred at the end of former President Barack Obama's term.
"I think that’s a perfectly viable explanation," retired American scientist Allan Frey told the Times. Frey is credited with a discovery in the 1960s that led to research in both the United States and Russia on using microwaves as weapons.
After holding Cuba responsible for either carrying out the attacks or failing to protect U.S. officials, the United States in September 2017 recalled more than half of its staff from the embassy in Havana and expelled 15 Cuban diplomats from Washington.
Cuba has denied any role in, or knowledge of, the incidents.
In June 2018, the State Department announced it had sent home U.S. government personnel from China after they reported similar symptoms.
The Times said Frey was the first to discover that the human brain can perceive microwaves as sound, a revelation that led to experimentation with microwave weapons in both the Soviet Union and the United States.
Russia's military categorized the new class of microwave weapons as "psychophysical" or "psychotronic."
Russian state-run news agency TASS reported last month that Russia is currently developing weapons for its troops based on "new physical principles," including "laser and microwave guns" and "sonic weapons."
The Times said the U.S. Defense Intelligence Agency warned in 1976 that Soviet research on microwaves showed potential for "disrupting the behavior patterns of military or diplomatic personnel."
A National Security Agency statement obtained by Washington lawyer Mark Zaid in 2014 said that a "hostile country" visited by a client in the late 1990s had "a high-powered microwave system weapon that may have the ability to weaken, intimidate, or kill an enemy over time and without leaving evidence," according to a copy of the statement published by the Times.
The statement said that "this weapon is designed to bathe a target's living quarters in microwaves, causing numerous physical effects, including a damaged nervous system."
The Times said the U.S. military also researched weapons applications of microwaves, with the U.S. Air Force registering a patent on an invention shown to beam comprehensible speech into someone's head.
It said U.S. Navy researchers explored using microwaves to induce sounds powerful enough to cause painful discomfort, and even immobilize the subject.
The Times said it was not known if Washington deploys such weapons.