BEIJING/WASHINGTON (Reuters) - An American citizen working at the U.S. consulate in the southern Chinese city of Guangzhou has reported suffering from “abnormal” sounds and pressure leading to a mild brain injury, the U.S. embassy said on Wednesday and China said it was investigating the incident.

The embassy, which issued a health alert to Americans living in China, said it could not link the case to health issues suffered by U.S. government staff in Cuba dating back to late 2016.

In Washington, U.S. Secretary of State Mike Pompeo said the United States was concerned about the “serious medical incident” and raised it with China’s visiting State Councillor Wang Yi.

“We notified China of what took place as best we know it and they have responded in a way that is exactly the right response,” Pompeo told a news conference with Wang. “We’re working together to resolve (this) ... I hope we can figure it out.”

Earlier, he told Congress that the incident in China was “medically similar” to one suffered by American diplomats in Cuba.

Wang, speaking through a translator, said Beijing was investigating the incident and “we haven’t found any organization or individual has carried out such a 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,” he cautioned.

The unnamed American citizen assigned to the consulate in Guangzhou had reported a variety of “physical symptoms” dating from late 2017 to April this year, the U.S. embassy in Beijing said in an email.

The worker was sent to the United States for further evaluation. “The clinical findings of this evaluation matched mild traumatic brain injury (MTBI),” the embassy said.

The State Department was taking the incident very seriously and working to determine the cause and impact, the embassy said. Pompeo said that medical teams were heading to Guangzhou to investigate the incident.

The State Department added that the Chinese government told the embassy it was also investigating and taking appropriate measures.

“We cannot at this time connect it with what happened in Havana, but we are investigating all possibilities,” a U.S. embassy official told Reuters.

The U.S. government on Wednesday issued a health alert to Americans in China, warning them about the incident it described as “subtle and vague, but abnormal, sensations of sound and pressure”.

U.S. Secretary of State Mike Pompeo gestures as he testifies at a hearing of the U.S. House Foreign Affairs Committee on Capitol Hill in Washington, U.S., May 23, 2018. REUTERS/Leah Millis

“While in China, if you experience any unusual acute auditory or sensory phenomena accompanied by unusual sounds or piercing noises, do not attempt to locate their source. Instead, move to a location where the sounds are not present,” the emailed alert said.

The U.S. government in October expelled 15 Cuban diplomats from the United States for what it said was Cuba’s failure to protect staff at the U.S. embassy in Havana from mysterious health incidents at one point thought to possibly have been acoustic “attacks”.

Staff there reported symptoms including hearing loss, dizziness, fatigue and cognitive issues, though Cuban officials dismissed the idea of acoustic strikes as “science fiction” and accused Washington of slander.

The cause of those incidents remains unresolved.

The Canadian government in April said it would remove families of diplomats posted to Cuba after Canadian personnel there in 2017 also reported similar health symptoms.