WASHINGTON — The State Department announced Friday that it is pulling more than half of its staff out of the US Embassy in Havana in the wake of mysterious attacks that have injured 21 people associated with the embassy.
The department will also issue an advisory warning to US citizens who travel to Cuba that they could face unusual risks.
Some of those attacked have suffered significant injuries, with symptoms including hearing loss, dizziness, tinnitus, balance and visual problems, headache, fatigue, cognitive issues, and difficulty sleeping.
Despite an intensive investigation by the FBI, the cause and perpetrators of the attacks remain a mystery. Some government experts have speculated that a sonic weapon or faulty surveillance device might have been to blame.
Some of the attacks occurred in hotels where State Department employees were temporarily staying, leading officials to worry that tourists and others could be affected. But there is no evidence so far that tourists or hotel employees have been affected, the department said.
“The decision to reduce our diplomatic presence in Havana was made to ensure the safety of our personnel,” Secretary of State Rex Tillerson said. “We maintain diplomatic relations with Cuba, and our work in Cuba continues to be guided by the national security and foreign policy interests of the United States.’’
“Cuba has told us it will continue to investigate these attacks, and we will continue to cooperate with them in this effort,” Tillerson said.
Josefina Vidal, Cuba’s head of US affairs said the announcement ‘‘will particularly affect cooperation in the mutual interest of both countries and the diverse exchanges taking place between Cuba and the United States,’’ the Associated Press reported
Vidal said Cuba wants to continue cooperation with Washington to ‘‘clear up these incidents.’’
State Department officials have decided they will not punish Cuba by forcing the country to reduce its own diplomatic staff in Washington, a decision that was immediately attacked by Senator Marco Rubio, a Republican from Florida who fiercely opposed Barack Obama’s decision to improve ties with Cuba.
Senator Patrick Leahy, a Vermont Democrat, said punitive measures would only play into the hands of the attackers. “Whoever is doing this obviously is trying to disrupt the normalization process between the United States and Cuba,” Leahy said. “Someone or some government is trying to reverse that process.
Friday’s announcement came just three days after Tillerson met with Bruno Eduardo Rodríguez Parrilla, Cuba’s foreign minister, in Washington, in a meeting that the Cuban government requested.
That meeting failed to persuade Tillerson that the Cubans could guarantee the safety of the remaining US employees in Havana, prompting him to decide to pull much of the embassy staff.
The staff remaining will carry out only emergency services, such as tasks to help US citizens in need. Routine visa functions for Cuban citizens will no longer be conducted in Havana.
Officials may soon direct Cubans seeking to travel to the United States to apply for visas at embassies or consulates in other countries.
US officials will continue to meet with their Cuban counterparts — but not in Cuba — until the cause of the attacks is uncovered, officials said. The most recent attack occurred in August.
Since the reestablishment of diplomatic relations in 2015, Cuba and the United States have been working together in areas including law-enforcement cooperation against drug-trafficking and human smuggling.
Tillerson had been considering closing the embassy, which had only recently reopened after decades of frosty relations between the two countries. But one of the reasons Tillerson will keep it open is a growing belief among US officials that the Cuban government was probably not responsible for the attacks.
A former senior US official said there was information that the Cubans were rattled by what had happened and were desperate to find the cause. A third country may have been responsible, the official said.
That the Cubans offered to let the FBI go to Havana and investigate represented a rare level of openness and was seen as yet another indicator that the Cubans themselves have been shaken by the incident.
US officials have said the attack may have been the work of a country like Russia or a rogue government unit.