(CNN) US Secretary of State Mike Pompeo said Wednesday that an incident involving a US government employee stationed in China who reported "abnormal sensations of sound and pressure" suggesting a mild brain injury has medical indications that are "very similar" and "entirely consistent" to those experienced by American diplomats posted in Havana.
US officials have issued a health alert in China following the incident. Additionally, the US State Department is looking into whether the incident is similar to what happened in Cuba in 2016 and 2017, a US diplomatic official told CNN, which the US government characterized as a "sonic attack." That incident led to a reduction in staffing at the US Embassy in Havana.
The official who fell ill was assigned to the city of Guangzhou in southern China and reported a range of physical symptoms from late 2017 through to April 2018, the State Department said. The employee was sent back to the United States for assessment.
The US Embassy in Beijing learned on May 18 that the clinical findings of the evaluation matched that of a "mild traumatic brain injury," an embassy spokeswoman told CNN.
Pompeo said the State Department is moving medical teams into place in Guangzhou and has asked for assistance from the Chinese government, which has committed to providing it.
Speaking alongside Pompeo in a press conference on Wednesday, Chinese Foreign Minister Wang Yi said China had been investigating the incident but hadn't found any source of the "sonic influence."
"We don't want to see that this individual case will be magnified, complicated, or even politicized. We hope people will not associate it with other unnecessary matters," Wang said, through a translator.
According to the alert issued by the US State Department on Wednesday, the cause of the injuries to the employee in China remains unknown, but officials were not aware of other similar symptoms among the diplomatic community in the country.
The spokeswoman at the US Embassy in Beijing told CNN the State Department was taking the incident "very seriously" and was working to determine the cause and impact of it.
"The Chinese government has assured us they are also investigating and taking appropriate measures," the spokeswoman said.
The State Department said in its Wednesday statement that anyone who experienced "unusual acute auditory or sensory phenomena" while in China should move away from the source of the noise.
The alert immediately raised comparisons with a series of unexplained incidents in Cuba that led to the withdrawal of most US personnel from the embassy in Havana. The cause of those incidents, reported in late 2016 and early 2017, still remains a mystery. Pompeo said Wednesday he expects to have a report from the accountability review board investigating the incidents in Cuba by the middle of next week.
At a congressional hearing in January, US officials detailed how personnel experienced a variety of symptoms including sharp ear pain, headaches, ringing in one ear, vertigo, disorientation, attention issues and signs consistent with mild traumatic brain injury or concussion. In nearly all cases, the ailments were preceded by some sort of "acoustic element," such as a "high-pitched beam of sound" or a "baffling sensation akin to driving with the windows partially open in a car."
Cuban officials previously denied they had anything to do with the diplomats' health problems and said the whole affair might be the result of mass hysteria.