WASHINGTON _ The mystery over why U.S. and Canadian diplomats in Cuba have developed hearing loss and other symptoms deepened Wednesday after a media report suggested they may have suffered brain damage.
Some officials believe the diplomats were injured by sonic waves from listening devices hidden in their homes or workplaces in Havana, but that has not been confirmed.
It is still not clear who planted the devices, and whether they were intended to cause harm.
"This is unprecedented," State Department spokeswoman Heather Nauert said. "We have not seen this anywhere."
Cuba has denied any responsibility and is cooperating with U.S. and Canadian investigators, she said.
CBS News reported Wednesday that it had reviewed medical records of some of the people affected. It said doctors had diagnosed mild traumatic brain injury and damage to the central nervous system.
The diplomats began reporting health problems, including hearing loss and dizziness, in December. Several cut short their assignments in Cuba because of the symptoms.
Secretary of State Rex Tillerson has cited the "health attacks" on diplomats but has not provided details. The State Department will not say how many Americans were affected.
