According to AP, 16 Americans working for the USA government in Cuba suffered symptoms as a result of activity attributed to a covert sonic device. and suffered severe hearing loss. "Some of them had been medically evacuated in order to receive medical treatment and testing", she said.
The State Department raised the incidents with the Cuban government over the course of several months and sent medical personnel to Havana, but have not been able to determine exactly what happened.
Last autumn, several U.S. diplomats began suffering unexplained deafness.
The incidents have prompted an ongoing investigation across different agencies, according to the department, and a number of diplomats have cut short their assignments in Cuba because of the attacks.
It is believed a sophisticated sonic weapon that operated outside the range of human audible sound was deployed either inside or outside the residences of U.S. diplomats in Havana, three U.S. officials told CNN.
CBS News obtained medical records from USA diplomats in Cuba that show doctors diagnosed them with brain injuries from possible sonic attacks while in Havana. The U.S. still hasn't identified the perpetrator, and Nauert said that Cuba is cooperating with the U.S. investigation.
They were unable to return to Cuba and many others have made a decision to leave, the source added.
At roughly the same time, Canada announced that at least one of its diplomats in Havana had suffered from similar symptoms.
At least 16 USA government employees suffered symptoms after a possible acoustic attack targeting the U.S. embassy in Cuba, the state department says.
In a story straight from the pages of a Cold War spy novel, the deterioration in health of the diplomats comes after a weird series of events in the autumn of past year when United States staff stationed at a newly reopened embassy in Havana first complained of feeling unwell.
Two senior U.S. government officials told CNN that more than 10 U.S. diplomats and their family members received treatment for similar ailments.
Some of the diplomats' symptoms were so severe that they were forced to cancel their tours early and return to the United States, officials said.
"We are aware of unusual symptoms affecting Canadian and USA diplomatic personnel and their families in Havana", Canadian spokesperson Brianne Maxwell said in a statement earlier this month.
In July, Raul Castro said in a speech that he hoped to continue improving US-Cuban relations, even as the Trump administration has taken a tougher stance toward Cuba.
The US expelled two Cuban diplomats from Washington in retaliation.
Two weeks ago Rex Tillerson, the U.S. secretary of state, condemned potential "health attacks" when reports of the symptoms first came to light.
The statement from the Cuban Foreign Ministry said it had been informed of the incidents on February 17 and had launched an "exhaustive, high-priority, urgent investigation at the behest of the highest level of the Cuban government".
It said the decision to expel two Cuban diplomats from the USA in retaliation was "unjustified and baseless".
"I doubt that it would be an intentional effort to derail normalization between people who opposed it", said William LeoGrande, co-author of "Back Channel to Cuba: The Hidden History of Negotiations Between Washington and Havana".