Two diplomats were expelled Wednesday from the Cuban embassy after several US envoys in Havana experiences unexplained symptoms and illnesses one official said includes potentially permanent hearing loss.
USA spokeswoman Heather Nauert said the first of the attacks, "which have caused a variety of physical symptoms" including hearing loss and signs of concussion, occurred in late 2016.
"We don't have any definitive answers about the source or the cause", of symptoms she characterized as not life-threatening. Further US action could follow if that investigation points to Cuban government targeting of US employees, officials said.
Citing an anonymous government official, CNN reports that the U.S. is still investigating the possibility this was an attack by a third country that might be trying to harm America's relations with Cuba. "Initially when they started reporting what I will just call symptoms, it took time to figure out what it was and this is still ongoing".
According to the Canadian national broadcaster, the government is working with Cuban authorities to determine what happened.
The Cuban Foreign Ministry said Wednesday it had started an "exhaustive" investigation into the weird incidents which the United States said had caused physical symptoms in its diplomats serving here. The AP also reports an investigation concluded that an advanced sonic weapon placed in or around the diplomats' homes was to blame.
The unexplained symptoms ultimately led the USA officials to leave Cuba.
The Federal Bureau of Investigating is looking into the matter, the report said.
Given Trump's aggresive posture against the Cuban regime - and thorn of his comments about Castro's crimes - the fact that a more aggessive response from the U.S.to what amounts to an attack of USA diplomats in Cuba does not add up.
Nauert confirmed that two Cuban diplomats were asked to leave on May 23rd and they've since departed.
The Ministry of Foreign Affairs reaffirms that Cuba complies rigorously and seriously with all its obligations arising from the 1961 Vienna Convention on Diplomatic Relations in connection with the protection and inviolability of diplomatic agents and the premises of diplomatic missions.
It said the decision to expel two Cuban diplomats from Washington had been "unjustified and unsubstantiated".
Investigators are exploring the possibility that another country, such as Russian Federation, carried out the attack without the Cuban government's knowledge.
"Cuba has never, nor would ever, allow the Cuban territory to be used for any kind of action against accredited diplomats or their families", the ministry said.
The embassy in Washington where the Cuban diplomats worked before they were expelled. We're taking that situation seriously and it's under investigation right now.
The incident threatens to set back relations between the two countries, which President Barack Obama took major strides to fix in 2015.
Cuba denies the allegation, but the U.S. has removed two Cuban diplomats from Washington DC in retaliation.
Relations with the country have become a significant issue in U.S. politics, he explained, thanks in part to the population of Cuban exiles in Florida, a battleground state in USA elections.