Washington: The US government expelled two Cuban diplomats in May, after Americans working at the US Embassy in Havana suffered unexplained physical ailments, the State Department said on Thursday.

US officials blamed a string of bizarre incidents that left a group of American diplomats in Havana with severe hearing loss, attributed to a covert sonic device.

Tourists ride vintage American convertibles as they pass by the United States embassy in Havana, Cuba, as tensions eased last year. Credit:AP

A small number of Americans began reporting symptoms at the end of 2016, and a few either were removed for medical treatment in the United States or asked to leave, State Department officials said on Thursday.

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.