WASHINGTON — Two more U.S. government workers have been confirmed to have been victims of invisible attacks in Cuba, the United States said Friday, raising the total to 24.

The tally has inched upward since the U.S. first disclosed in August that embassy workers and their families in Havana had been harmed by unexplained, mysterious incidents. The Trump administration later said it had determined the incidents were “specific attacks” that are ongoing, but investigators have not yet identified a weapon or a culprit.

The disclosure that 24 people have been harmed suggests that nearly half the American government workers serving in Cuba have been attacked. The U.S. had roughly 50 personnel posted to the embassy in Havana until earlier this month when, in response to the attacks, the State Department pulled out roughly 60 percent of the staff. Yet some of the victims were spouses of U.S. workers, and several were temporary workers who rotated in to Cuba for short-term stints.

State Department spokeswoman Heather Nauert said the two additional victims “do not reflect new attacks.”

“The assessments are based on medical evaluations of personnel who were affected by incidents earlier this year,” Nauert said.

Nauert said the most recent attack is still believed to have been near the end of August. A U.S. official told The Associated Press previously that this attack occurred Aug. 21. The official wasn’t authorized to disclose the exact date and requested anonymity.

“Our personnel are receiving comprehensive medical evaluations and care,” Nauert said.

The attacks started last year and affected American diplomats, intelligence officials and their spouses in Havana. They began in staffers’ homes in Havana, but the AP disclosed in September that they later occurred in hotels as well. The attacks in hotels began after the U.S. complained to President Raul Castro’s government, and Cuban security officials dramatically increased patrols around the U.S. workers’ homes, officials said.

Cuba has vehemently denied any knowledge or involvement in the attacks, emphasizing its eagerness to cooperate with the investigation being led by the FBI. The United States hasn’t blamed Cuba or any other actor of perpetrating the attacks, but has faulted Castro’s government for failing to stop them, arguing it’s Cuba’s responsibility under international law to protect foreign diplomats on its soil.

“I do believe Cuba’s responsible. I do believe that,” President Donald Trump said last week. “And it’s a very unusual attack, as you know. But I do believe Cuba is responsible.”