Oct. 20 (UPI) -- Two more government employees have experienced symptoms associated with a mysterious attack on U.S. diplomats in Havana, Cuba, the U.S. State Department said Friday.
Spokeswoman Heather Nauert said a total of 24 government personnel "experienced health effects from the attacks."
The attack, which officials have described as sonic or acoustic in nature, was first reported in August.
Earlier this month, the State Department also said U.S. citizens not working for the government are reporting similar symptoms, including mild traumatic brain injury, permanent hearing loss, loss of balance, headaches and brain swelling.
Nauert's statement Friday said the two new reports of illness were based on medical evaluations conducted earlier this year.
"They do not reflect new attacks," she said. "As noted before, the most recent medically confirmed attack occurred near the end of August."
She said those who had experienced symptoms were undergoing medical care and that the department can't rule out new cases in the future.
On Sept. 29, the United States pulled all non-emergency staff from the embassy in Havana.
"Until the government of Cuba can ensure the safety of our diplomats in Cuba, our embassy will be reduced to emergency personnel in order to minimize the number of diplomats at risk of exposure to harm," the State Department said at the time.
Cuban officials have denied any involvement in the incidents.
"The Cuban government has never perpetrated nor will it ever perpetrate attacks of any kind against diplomats," the Cuban Foreign Ministry said.