American and Canadian diplomats based in Cuba suffered mild traumatic brain injury and damage to the central nervous system in a suspected sonic weapon attack on their homes.
The diplomats, based at Havana's US Embassy, began complaining about a series of symptoms ranging from hearing loss and nausea to headaches and balance disorders, in late 2016, according to the State Department.
An investigation concluded an advanced sonic weapon had been operated outside the range of audible sound, either inside or outside officials' residences.
Medical records, seen by CBS News, now reveal the diplomats appeared to have suffered mild traumatic brain injury and even suspected damage to their central nervous systems in the attack. Many of the diplomats cut short their assignments in Cuba because of the attacks.
Cuba has denied any involvement in the attacks.
American and Canadian diplomats based in Cuba suffered mild traumatic brain injury and damage to the central nervous system in a suspected sonic weapon attack on their homes (Pictured, a supporter waves flags of the United States and Cuba in front of the country's embassy in Washington, DC in July 2015)
Canada has revealed that at least one of its officials in Havana has also been treated for hearing loss.
'The government is actively working – including with US and Cuban authorities – to ascertain the cause,' said a spokesman for Canada's diplomatic service. She added that officials did not believe Canadian tourists had been affected.
The US embassy in Cuba reopened in 2015 as part of President Barack Obama's re-establishment of diplomatic relations. Canada helped broker talks between the countries. Last autumn, several US diplomats began suffering unexplained deafness.
The source says that the diplomats have also been subjected to harassment, had their cars vandalized, been under almost constant surveillance, and even had home break-ins.
The US expelled two Cuban diplomats from Washington in retaliation.
A source told CBS that further attacks on US embassy workers still in Cuba have continued.
An American doctor had visited Havana in spring to assess the diplomats, who underwent a series of tests.
The State Department has not yet identified a definitive source of the attacks, but officially reminded Cuban authorities of their international obligations to protect diplomats.
In fall 2016, the US diplomats reportedly began suffering unexplained losses of hearing. After an investigation, officials concluded that the diplomats had been attacked with an advanced sonic weapon that operated outside the range of audible sound (Pictured, the US Embassy in Havana in December 2015)
'We hold the Cuban authorities responsible for finding out who is carrying out these health attacks on not just our diplomats but, as you've seen now, there are other cases with other diplomats involved,' Secretary of State Rex Tillerson told reporters earlier this month.