The State Department has expelled two diplomats from the Cuban Embassy in Washington following a series of unexplained incidents in Cuba that left USA officials there with physical symptoms that one official said includes potentially permanent hearing loss.
Cuba and the United States reestablished diplomatic ties in 2015, following a political and economic standoff that lasted five decades.
A U.S. government official told CNN that the "who, where and when point to an attack".
Cuba's Foreign Ministry said it was investigating the allegations. She did not say how many USA diplomats were affected or confirm they had suffered hearing loss, saying only that they had "a variety of physical symptoms". "It's caused a variety of physical symptoms in these American citizens who work for the US government".
Spokeswoman Heather Nauert said the two Cubans were asked to leave the USA on May 23 after Americans in Cuba "reported incidents which have caused a variety of physical symptoms", causing them to leave the island.
Spokeswoman Heather Nauert said the first of the attacks, which are said to have caused a variety of physical symptoms, including hearing loss and signs of concussion, occurred in late 2016.
The health symptoms included severe hearing loss, possibly caused by a covert sonic device, and affected were a group of American diplomats in Havana and at least one Canadian diplomat, the Associated Press reported.
According to CNN, US diplomats in Havana "had complained that they suffered harassment from Cuban officials and frequently had their homes and cars broken into".
Investigators are trying to determine whether Cuba "placed sonic devices that produce non-audible sound inside or outside the residences of roughly five United States embassy staffers with the intent of deafening them", The Guardian says.
Cuba's state-run security and surveillance services spend much of their time tracking American envoys through the island nation.
"We believe that the Cubans are responsible, like any host country is responsible for the security and integrity of the diplomats who are on its territory", said Mr. Tillerson, who was speaking at the side of the american president Donald Trump with which he came to speak at Bedminster (New Jersey) about the north Korean crisis.
Nauert said investigators did not yet have a definitive explanation for the incidents but stressed they take them "very seriously", as shown by the Cuban diplomats' expulsions.
Relations between the United States and Cuba were restored by then U.S. president and his Cuban counterpart Raul Castro in 2015 after a half-century break. The use of sonic devices to intentionally harm diplomats would be unprecedented.