UNITED NATIONS — Cuba so far hasn’t unearthed any information about who or what caused a mysterious series of health incidents that have affected U.S. and Canadian diplomats in Havana, its top diplomat said Friday.

Foreign Minister Bruno Rodriguez Parrilla told the U.N. General Assembly that early results from its investigation have to date “found no evidence whatsoever that could confirm the causes or the origin” of the problems, though the inquiry is continuing.

“It would be unfortunate if a matter of this nature is politicized,” Rodriguez added in a speech that also laid into President Trump as a leader with a “supremacist vision” of “America First.” Trump slammed Cuba’s leadership as “corrupt and destabilizing” in his own General Assembly speech Tuesday.

At least 21 Americans and several Canadians in Havana’s diplomatic community have suffered hearing loss and other symptoms believed to have come from some sort of sonic attack.

Some of the Americans have permanent hearing loss or concussions, while others suffered nausea, headaches and ear-ringing. Some are struggling with concentration or common word recall.

U.S. Secretary of State Rex Tillerson has described the incidents as “health attacks,” though the State Department has since used the term “incidents.” In their wake, Tillerson said Sunday that the U.S. was considering closing its recently reopened Havana embassy.

Cuba has said it knows nothing about the health events.