A series of mysterious "incidents" has left Americans working at the United States embassy in Havana with medical "symptoms", forcing them to return home and prompting the USA government to expel a pair of Cuban diplomats from their own country's embassy in Washington, DC. "It's caused a variety of physical symptoms in these American citizens who work for the USA government".
It was not immediately clear what had happened, with spokeswoman Heather Nauert saying there were no "definitive answers about the source or cause". Further U.S. action could follow if that investigation points to Cuban government targeting of U.S. employees, officials said. "The government is actively working - including with U.S. and Cuban authorities - to ascertain the cause".
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 Thursday.
It has been suggested that covert sonic devices which emit inaudible sound waves may have been placed either inside or outside the diplomats residences in the Cuban capital.
However, the Associated Press, citing unnamed sources, reported Wednesday that the symptoms included hearing loss, which in some cases is believed to be permanent.
The U.S. diplomatic mission in Havana was only elevated to status of embassy in 2015, when then-President Obama and Cuban President Raul Castro reestablished full relations after half a century of Cold War hostilities. The mysterious incidents led to the United States expelling two Cuba officials from their Washington, D.C. embassy.
Nauert confirmed during Wednesday's briefing that the investigation is ongoing and authorities are still trying to determine what afflicted US Embassy staffers.
An exterior view of the U.S. Embassy is seen in Havana, Cuba, June 19, 2017. Officials cautioned the AP that Cuba may have been unaware the attacks were happening, and that a third country like Russian Federation may have been responsible. She added a reminder that "the Cuban government has a responsibility and obligation to protect our diplomats". "And we take this extremely seriously".
USA diplomats in Cuba said they suffered occasional harassment for years after the restoration of limited ties with the communist government in the 1970s, harassment reciprocated by US agents against Cuban diplomats in Washington.
"Personal harm to USA officials shows the extent the Castro regime will go and clearly violates global norms".
"Cuban territory to be used for any action against accredited diplomatic officials or their families, without exception".
In a statement, the Ministry of Foreign Affairs of Cuba said it took the issue seriously and acted in a professional manner in an attempt to clarify facts surrounding the situation by launching an investigation.