The U.S. embassy in China issued a health alert on Wednesday to all Americans living in the country after a U.S. citizen working at the consulate in Guangzhou reported symptoms disturbingly similar to the “sonic attack” victims at the U.S. embassy in Cuba in 2016.

The patient in Guangzhou reported “physical symptoms” that began in late 2017 and ran through April of this year. The individual has been diagnosed with a “mild traumatic brain injury.”

“A U.S. government employee in China recently reported subtle and vague, but abnormal, sensations of sound and pressure,” said Wednesday’s health alert. “The U.S. government is taking these reports seriously and has informed its official staff in China of this event. We do not currently know what caused the reported symptoms and we are not aware of any similar situations in China, either inside or outside of the diplomatic community.”

“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 U.S. embassy advised.

24 Americans who worked at the U.S. embassy in Cuba in 2016 reported symptoms including hearing loss, headaches, and cognitive issues. 18 of the subjects reported hearing a weird high-pitched noise in their homes or hotel rooms before exhibiting the symptoms.

U.S. Secretary of State Mike Pompeo was surprisingly blunt in stating on Wednesday that the symptoms reported by the patient in China are “very similar” and “entirely consistent” with the Cuba incident.

“The Chinese government has assured us they are also investigating and taking appropriate measures,” a spokeswoman for the U.S. embassy in Beijing told CNN on Wednesday. Pompeo also said the Chinese government has promised to assist.

Pompeo added that the State Department is sending medical teams to Guangzhou. The person who reported the symptoms has already returned to the United States for evaluation and treatment.