In a statement Tuesday, Secretary of State Rex Tillerson confirmed that the United States has expelled 15 Cuban officials from the communist nation’s embassy in Washington, D.C., in response to attacks on nearly two dozen Americans working in Havana.

Various news agencies had previously reported the United States was considering removing up to two-thirds of Cuba’s embassy staff from American soil.

The State Department has confirmed at least 22 cases of Americans working for the U.S. government in Cuba suffering illness and injury following an unexplained string of “attacks” using advanced technology in and around the embassy. Various reports have described the attacks as acoustic in nature, using sound waves to cause hearing loss, headaches, concussion-like symptoms, and brain damage.

“On October 3, the Department of State informed the Government of Cuba that it was ordering the departure of 15 of its officials from its embassy in Washington, D.C.,” Tillerson said in his statement. “The decision was made due to Cuba’s failure to take appropriate steps to protect our diplomats in accordance with its obligations under the Vienna Convention. This order will ensure equity in our respective diplomatic operations.”

The statement explained that the move followed the mass withdrawal of American personnel from Cuba and warnings to all U.S. citizens to avoid the communist dictatorship, to which Americans can only travel under certain categories of visits. “Until the Government of Cuba can ensure the safety of our diplomats in Cuba, our embassy will be reduced to emergency personnel to minimize the number of diplomats at risk of exposure to harm,” Tillerson said.

Tillerson went on to assure that the United States will “continue to maintain diplomatic relations with Cuba, and will continue to cooperate with Cuba as we pursue the investigation into these attacks.”

Late last week, Tillerson announced in a similar statement that the State Department would withdraw all “non-essential” staff from the Havana embassy and urge all Americans to avoid Cuba, as the attacks appear to have taken place in areas “frequented by U.S. citizens” not affiliated with the government. It was the first prominent use of the word “attacks” to describe the events in question, as spokeswoman Heather Nauert had insisted on referring to them as “incidents” in prior press conferences.

“The decision to call them attacks reflects that there’s been a consistent pattern of our people being affected, and there’s no other conclusion that we could draw,” a State Department official told reporters on a conference call Tuesday following the expulsion of Cuban officials. The official also confirmed a new case of a diplomat affected by the attacks in question, raising the number to 22.

“We will need full assurances from the Cuban Government that these attacks will not continue before we can even contemplate returning personnel,” the official asserted, adding that the Cubans expelled are “not being declared persona non grata. And we expect them to leave within seven days.”

On Monday, both McClatchy and the Associated Press reported that the expulsion was underway. McClatchy cited three U.S. sources who confirmed the move before the announcement and suggested that “the Trump administration will kick nearly two-thirds of Cuba’s embassy personnel out of the United States” in response to the acoustic attacks on Americans. AP put the number at “60 percent.”

While the State Department statement did not describe it as such, an unnamed source called the move “reciprocity” for the American injuries in the McClatchy report, while sources called it a “direct response” to the attacks to the AP.

“The United States will formally tell Cuba to pull the diplomats, but won’t expel them forcibly unless Havana refuses, the officials said,” the AP reported yesterday.

According to the AP report, America had stationed “roughly 50 workers” at the Havana embassy, meaning that nearly half of these suffered symptoms of the acoustic attacks.

The Cuban government derided the United States through its state media outlets following the reports that the U.S. would withdraw staff from Havana, dismissing the move as “irresponsible.” Cuban diplomats also referred to the Trump administration’s move to protect personnel as “hasty.”

While the United States has repeatedly affirmed it does not blame the Cuban communist regime for the attacks in question, Cuban former political prisoners have testified to being tortured with advanced sonic devices that appear to resemble what reports suggest is being used in this instance.

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