At least 16 US embassy employees in Cuba have experienced symptoms related to mysterious 'incidents' in Havana, officials have confirmed.
Both the Cuban and US authorities earlier this month announced that investigations are underway after reports that a number of US diplomats suffered serious hearing loss while stationed in Havana.
The US said two Cuban diplomats had been expelled in response to 'incidents' in Cuba, but officials have divulged few details of what took place.
However, the Associated Press claimed that some embassy staff in the Cuban capital were last Autumn left with "severe hearing loss attributed to a covert sonic device".
Some individuals are said to have had such severe symptoms that they were forced to return to the US.
At least one Canadian diplomat is also said to have been affected.
CBS News this week reported that some individuals affected experienced conditions as serious as 'mild traumatic brain injury' and 'likely damage to the central nervous system'.
The reports emerged only two years after the US embassy in Havana re-opened, as part of improved diplomatic relations between the two states under Barack Obama.
In the latest update, US State Department spokesperson Heather Nauert explained: "We only now have the confirmation of the number of Americans who have been affected by this. We can confirm that at least 16 US government employees - members of our embassy community - have experienced some kind of symptoms. They have been provided medical treatment in the United States as well as in Cuba.
"We take this situation extremely seriously. We are trying to provide them the help, the medical care, the treatment, and the support that they need."
She added: "I know that various governments have seen that kind of behavior from the Cuban Government in the past. But again, we’re not assigning responsibility at this point. We don’t know who the perpetrator was of these incidents."
Cuban authorities have previously insisted they would never "allow that the Cuban territory be used for any action against accredited diplomatic agents or their families".
