The United States is testing two staff members of its Cuban embassy in Havana amid concerns that they may have been the target of sonic attacks.
A spokesman for the State Department said they were being tested for brain injuries.
Last year, 24 employees of the Cuban embassy suffered a mysterious illness after reporting “auditory sensations.”
Earlier this week, the United States recalled diplomats from Guangzhou city in southern China after they reported strange symptoms and sounds.
The incidents have raised concerns that a government or agency may be targeting the US with a new type of sonic weapon.
Cuba denied having addressed the embassy staff, and the United States has not blamed the country’s government for the alleged attacks.
Those affected have suffered a series of symptoms that include hearing loss, dizziness, fatigue, cognitive problems and loss of sleep.
The last two staff members of the Cuban embassy could be “potentially new cases,” but they must still be “medically confirmed,” said an official with the US State Department to the Associated Press news agency.
It is said that they were taken to the University of Pennsylvania, where doctors are treating people with alleged injuries.
Last month, the US Department of State urged his staff in China to alert them to any hearing problems or abnormal vision after an employee reported mysterious symptoms.