Employees at the American consulate in Guanzhou, China have fallen ill and exhibited symptoms similar to those displayed by U.S. workers in Cuba, who in 2016 also heard strange noises.
At least two diplomats have recently been evacuated from China with the number possibly to rise soon, the New York Times reports. An American medical team has flown in to Southern China to check the diplomats and their families.
For months, American officials have been worried that their diplomats have been subjected to targeted attacks involving odd sounds, leading to symptoms similar to those "following concussion or minor traumatic brain injury," the State Department says.
The cases in China have broadened a medical mystery that started in 2016, when American Embassy employees and their family members began falling ill in Havana. In all, 24 of them were stricken with headaches, nausea, hearing loss, cognitive issues and other symptoms after saying they heard odd sounds. The issue has roiled relations with Cuba, which immediately fell under suspicion, and led the United States to expel Cuban diplomats.
Investigations are still underway in China in an attempt to figure out the true cause of the symptoms, including whether sonic attacks are actually to blame. Other theories about what could be causing the symptoms have included toxins, listening devices that accidentally emitted harmful sounds, or even mass hysteria.
Shortly after the first reports of such illnesses in Guanzhou, Secretary of State Mike Pompeo told Congress they "are very similar and entirely consistent with the medical indications that have taken place to Americans working in Cuba."
The consulate in Guanzhou is designed to withstand electronic eavesdropping and other hi-tech intelligence intrusions.
While the sonic attacks in Cuba initially rattled U.S.-Cuba relations, the occurrence of similar symptoms in Guangzhou has raised suspicions about whether China, Russia, or another country might be to blame.