President Donald Trump blamed Cuba on Monday for the mysterious attacks that injured 22 U.S. diplomats and other Americans, but gave no details.
"I do believe Cuba is responsible. I do believe that. And it's a very unusual attack, as you know," Trump said in a White House Rose Garden news conference.
But the president did not say exactly who he thinks was behind the attacks, including Raul Castro's government.
U.S. investigators believe America diplomats and others in Havana may have been bombarded with a sonic device earlier this year that gave them hearing loss, dizziness, headaches and tiredness.
The devices were placed outside their homes. So far, the investigators have no clues who was responsible or exactly what caused the sounds.
The United States recalled a number of non-essential diplomats and their families from Cuba and expelled 15 Cubans from the embassy in Washington.
Cuba has denied any involvement in the attacks and says it is dedicated to the safety of all foreign diplomatic personnel.