At least 16 US government employees associated with the US embassy in Havana have suffered unexplained health problems, including hearing loss, that officials believe could be caused by a covert sonic device.

The US State Department spokeswoman Heather Nauert said on Thursday that reports of the “incidents” had started in autumn 2016 and ended in April this year.

Earlier, US officials had said the symptoms appeared to have resulted from a covert sonic device. But Nauert said on Thursday no device nor any perpetrator had yet been found and that Cuba was cooperating with the US investigation.

“We take this situation extremely seriously,” Nauert added.

Diplomats and their spouses were among those treated in May by doctors in Cuba or the US, Nauert said. Some of the 16 are still in Cuba, while others have returned to the US.

Earlier this month the US state department revealed that it had expelled two diplomats from the Cuban embassy in Washington in May after Americans in Cuba “reported incidents which have caused a variety of physical symptoms”.

Cuba employs a huge state security apparatus to facilitate constant surveillance of potentially thousands of people, and US diplomats are among the most closely monitored.

Like all foreign diplomats in Cuba, US officials live in housing owned and maintained by the Cuban government.

In the autumn, officials said the affected diplomats and their spouses began to experience symptoms of hearing loss so severe and puzzling that an investigation was launched, and it was determined that they were at risk. They were allowed to leave Cuba, the officials said.



Harassment of US diplomats in Cuba is not uncommon and dates back to the restoration of limited ties with the communist government in the 1970s.

Canada’s government has said at least one Canadian diplomat in Cuba has also been treated for hearing loss.

Associated Press contributed to this report

