The United States is considering closing its embassy in Havana in response to an alleged sonic attack on US personnel in Cuba, Secretary of State Rex Tillerson said on Sunday.
"We have it under evaluation".
"It's a very serious issue with respect to the harm that certain individuals have suffered", Tillerson said.
Five Republican senators on Friday called for the Trump administration to retaliate against the Cuban government by expelling Cuban diplomats and possibly shuttering the USA embassy there over attacks that began in late 2016.
After remaining shuttered for almost five decades, the Havana embassy reopened in 2015 as part of former President Barack Obama's warming of Cuban relations.
At least five Canadian diplomats and their families were also affected by "sonic attacks", though none suffered permanent injury, public broadcaster CBC reported Friday.
The American Foreign Service Association - the labor union representing USA diplomatic and global aid personnel - spoke to 10 of those who received treatment and said their diagnoses included mild traumatic brain injury and permanent hearing loss.
The State Department has called the attacks "unprecedented" and has warned Havana it is responsible for the safety of envoys working on its soil - without saying who it believes was behind them. Cuba has denied any responsibility for the ailments and has said it will work with the U.S.to find answers.