The U.S. has ordered the expulsion of 15 Cuban diplomats from their embassy in Washington following mysterious attacks on American officials in Havana.
Secretary of State Rex Tillerson said, however, that Washington would maintain diplomatic relations even though the size of the USA mission in Havana would be reduced to a minimum.
According to Secretary of State Rex Tillerson, Cuba failed to "take appropriate steps" following alleged "attacks" on American personnel in the Caribbean country.
Though Havana is likely to view the move as unwarranted retaliation, USA officials said the goal wasn't to punish the communist-run island, but to ensure both countries have a similar number of diplomats in each other's capitals.
"We have underscored repeatedly to the Cuban government its responsibility for the safety, wellbeing, security and protection of our diplomatic staff under the Vienna Convention in Havana", the state department official said.
The attacks, which United States officials initially suggested could have come from some sort of covert acoustic device, have affected at least 22 U.S. embassy staff in Havana over the past few months.
The state department said the expulsions did not necessarily mean the U.S. had concluded that the Cuban government was responsible for a variety of symptoms including hearing loss, headaches and cognitive problems, but it said Cuba had failed to live up to its obligations under global law to protect diplomats.
The latest move by the Trump administration is a blow to former President Barack Obama's legacy to improve relations between the US and Cuba, two Cold War foes who did not have diplomatic relations until the Obama administration restored them.
U.S. relations with Havana were only fully restored in 2015, and have deteriorated since President Donald Trump took office in January.
The Cuban diplomats being expelled will not be deemed "persona non grata", officials said, a designation that would prevent them from ever returning to USA soil. The US has said the FBI is leading the investigation.
The State Department informed the Cuban ambassador in a Tuesday phone call that the diplomats had one week to vacate the country.
The decision announced Tuesday is certain to deepen the rift between the two countries over what the State Department has called "specific attacks" on US diplomats during the past 10 months.
He emphasized that this does not change diplomatic relations with the country.
Still, the administration has pointedly not blamed Cuba for perpetrating the attacks, and officials have spent weeks weighing how to minimize the risk for Americans in Cuba without unnecessarily harming relations or falling into an adversary's trap.
In August, the State Department said it was confident that the attacks had stopped but later said that its Havana staff is still at risk.
Bruno Rodriguez spoke on Tuesday after the U.S. government expelled 15 of Cuba's diplomats to protest against its failure to protect Americans from the unexplained attacks. During a speech at the UN General Assembly last month, Cuban Foreign Minister Bruno Rodriguez warned Trump not to let the issue be "politicized".
Last Friday, the State Department issued a travel warning advising all American visitors to stay away because their safety could not be guaranteed, a measure that is certain to harm Cuban tourism, the most dynamic segment of the economy.