Two weeks ago, the agency said one government employee in Guangzhou experienced "vague, but abnormal, sensations of sound and pressure," similar to the unexplained incidents — sometimes described as "sonic attacks" — that recently sickened staffers in Cuba.
The State Department says it sent a medical team to Guangzhou to screen any employees or family members who requested a test.
On Wednesday, State Department spokesperson Heather Nauert said the employees were sent to the U.S. for a "further evaluation and a comprehensive assessment of their symptoms and findings."
A department spokesperson said the agency was not specifying the exact number of people evacuated, saying it was due to medical privacy concerns.
On Tuesday, Secretary of State Mike Pompeo announced a task force to respond to the "unexplained health incidents."
He said that as of now, 24 government employees or family members who worked in Cuba had confirmed symptoms "similar to those noted following concussion or minor traumatic brain injury." The Guangzhou employee was found to have similar symptoms on May 16.
The symptoms, which first appeared in late 2016 in Havana, include "dizziness, headaches, tinnitus, fatigue, cognitive issues, visual problems, ear complaints and hearing loss, and difficulty sleeping."
The Journal of the American Medical Association reported in March that a study of 21 former Havana staffers found "most experienced persistent cognitive, balance, hearing, oculomotor dysfunction, or all 4, as well as sleep impairment and headaches."
One of the study's authors, Randel Swanson, described the symptoms as being "like a concussion without a concussion."
The government says it still doesn't know the cause.
In February, the nonprofit news organization ProPublica detailed the frustrations of U.S. government officials investigating the mysterious illnesses in Cuba:
"After nearly a year of investigation that has drawn on intelligence, defense and technology expertise from across the U.S. government, the FBI has been unable to determine who might have attacked the diplomats or how. Nor has the bureau ruled out the possibility that at least some of the Americans weren't attacked at all. Officials who have been briefed on the inquiry described it as having made strikingly little progress in answering the basic questions of the case, with frustrated FBI agents reporting that they are running out of rocks to overturn."
The U.S. first pulled out all nonessential staff in Cuba in September, followed shortly after by the expulsion of 15 Cuban diplomats from their U.S. post. Cuba has denied involvement.
China's government said Thursday that it investigated and could not find anything to cause the described symptoms, NPR's Anthony Kuhn reports from Beijing. The foreign ministry said it takes its obligation to protect foreign diplomats seriously and is open to conducting further investigations if requested by the U.S.
The Associated Press reported that the evacuated staff members from China are being sent to the University of Pennsylvania for testing, where doctors have tested former employees stationed in Havana.
The U.S. Consulate in Guangzhou, in southern China, officially opened in 1979 and moved to its current location in 2013. It's one of five consulates the U.S. operates in China, along with its main embassy in Beijing, according to the State Department's website.
