NEW YORK -- Secretary of State Rex Tillerson said Sunday that President Donald Trump's administration is considering closing down the U.S. Embassy in Havana after a series of unexplained incidents harming the health of American diplomats.
Tillerson's comments were the strongest indication to date that the United States might mount a major diplomatic response, potentially jeopardizing the restart of relations between the U.S. and Cuba. The two former foes reopened embassies in Washington and Havana in 2015 after a half-century of estrangement.
At least 21 Americans who worked in the U.S. Embassy in Cuba have reported medical problems since late last year, when percussive attacks on their residences began. The incidents apparently continued into this year. Two Cuban diplomats have been expelled from the embassy in Washington in response.
The State Department did not comment publicly about the incidents until August, months after the problems were uncovered.
[PRESIDENT TRUMP: Timeline, appointments, executive orders + guide to actions in first 200 days]
"We have it under evaluation," Tillerson said of a possible embassy closure. "It's a very serious issue with respect to the harm that certain individuals have suffered. We've brought some of those people home. It's under review."
Of the 21 medically confirmed U.S. victims -- diplomats and their families -- some have permanent hearing loss or concussions, while others suffered nausea, headaches and ear-ringing. Some are struggling with concentration or common word recall, The Associated Press has reported.
Some victims felt vibrations or heard loud sounds mysteriously audible in only parts of rooms, leading investigators to consider a potential "sonic attack." Others heard nothing but later developed symptoms.
The FBI is investigating what the union representing foreign service officers describes as "sonic harassment attacks" on the diplomats. A Canadian diplomat also reported similar problems.
Tillerson once called the events "health attacks," but the State Department has since used the term "incidents" while emphasizing the U.S. still doesn't know what has occurred. Cuba has denied any involvement or responsibility and has said it's eager to help the U.S. resolve the matter.
The U.S. has said the tally of affected Americans could grow.
The last reported incident was on Aug. 21, according to a U.S. official briefed on the matter. The official wasn't authorized to discuss the matter publicly and requested anonymity.
A decision to close the embassy, even temporarily, would deal a blow to the delicate detente that President Barack Obama and Cuban leader Raul Castro announced in late 2014. The next year, embassies were reopened and restrictions on travel and commerce eased -- signs of a warming relationship that displeased some hard-liners in Cuba's government. Trump has reversed some of the changes, but he left many in place.
Tillerson spoke on CBS' Face the Nation as world leaders and top diplomats arrived in New York for annual U.N. General Assembly meetings. Trump will give his first U.N. speech this week.
Cuba is also represented at the U.N., but it's not expected that Trump will meet with any Cuban leaders or officials.
The U.S. hasn't identified either a culprit or a device. Investigators have explored the possibility of sonic waves, an electromagnetic weapon, or an advanced spying operation gone awry, U.S. officials briefed on the probe said. The U.S. hasn't ruled out that a third country or a rogue faction of Cuba's security services might be involved.
In Washington, lawmakers in Congress have been raising alarm over the incidents, with some calling for the embassy to be closed. On Friday, five Republican senators wrote to Tillerson, urging him to not only close the embassy, but also to kick all Cuban diplomats out of the United States.
"We ask that you immediately declare all accredited Cuban diplomats in the United States persona non grata and, if Cuba does not take tangible action, close the U.S. Embassy in Havana," said the group of lawmakers, which included Sen. Tom Cotton of Arkansas, who led the effort, and Sen. Marco Rubio of Florida, a Cuban-American and critic of the U.S. detente.
"Cuba's neglect of its duty to protect our diplomats and their families cannot go unchallenged," the lawmakers said.
The incidents have frightened Havana's tight-knit diplomatic community, raising concerns about the potential scope. At least one other country, France, has tested embassy staff for potential sonic-induced injuries, the AP has reported.
Information for this article was contributed by Josh Lederman of The Associated Press and Carol Morello of The Washington Post.
A Section on 09/18/2017