The US State Department said it is investigating whether the illnesses were acoustic attacks or a form of viral warfare.
Relations between the US and Cuba were officially restored in 2015, but over the last two years, they've deteriorated again.
At least 26 US diplomats, intelligence officials and family members have suffered mystery health problems in Havana, which according to the US happened because they came under attack.
Recent reports have suggested investigators are focusing on the possibility that some sort of microwave device may be responsible and that Russia, which has long had close ties with Cuba, is the leading suspect for the attacks.
TRT World's Ed Augustin reports.