President Donald Trump on Monday said he believes the Cuban government was responsible for a series of mysterious sonic attacks against U.S. diplomatic personnel that has strained relations between Washington and Havana.

Trump told reporters that he agreed with the assessment of White House Chief of Staff John Kelly, who said last week that the administration believes the Cuban government could have stopped the attacks.

“I do believe Cuba is responsible,” the president told reporters during a press conference at the White House.

It was unclear if Trump meant that the Cuban government orchestrated the attacks or didn’t do enough to protect U.S. diplomats from whoever did. The Department of State said earlier this month that it doesn’t know who carried out the attacks.