The US embassy in China issued a health alert Wednesday after a US government employee experienced an "abnormal" sound and suffered a mild brain injury - in an incident reminiscent of a mysterious illness that hit diplomats in Cuba.
The US State Department is looking into whether the incident is a "sonic attack", a US diplomatic official told CNN, similar to what happened in Cuba in 2016 and 2017, which led to a reduction in staffing at the nation's US embassy in Havana.
A health alert has been issued by the U.S. embassy in Guangzhou, warning Americans living or working in China to take action if "unusual sounds or piercing noises" are heard.
"The U.S. government is taking these reports seriously and has informed its official staff in China of this event", the embassy said in a statement.
Meanwhile, the US State Department stated that the US consulate worker in southern China that had earlier reported symptoms similar to those of mild brain injury and head concussion returned to the US for further examination.
The US 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. and Chinese authorities are investigating the matter after the employee, who was assigned to the southern city of Guangzhou, was diagnosed with mild traumatic brain injury (MTBI), said embassy spokeswoman Jinnie Lee.
CHINA EMBASSY MEDICALLY SIMILAR The incident been compared to a suspected'sonic attack in Cuba
Past year in Cuba, the U.S. reported that some of its personnel and family members experienced a range of ailments, some after hearing an unusual sound.
A spokesperson at the U.S. Embassy in Beijing confirmed to CBS News that from late 2017 through April 2018, a U.S. government employee assigned to the Guangzhou Consulate reported "a variety of physical symptoms". "Instead, move to a location where the sounds are not present", the State Department advises.
Responding to these claims, the Cuban Foreign Ministry denied any Cuban involvement in the alleged attacks.
The State Department warned those who experience any "unusual acute auditory or sensory phenomena accompanied by unusual sounds or piercing noises" to leave the area immediately. Previous victims of similar attacks in Cuba suffered permanent hearing loss, severe headaches, loss of balance, brain swelling, and disruption to cognitive functions.
The alert immediately raised comparisons with a series of unexplained incidents in Cuba that led to the withdrawal of most USA personnel from the embassy in Havana.
The cause of those incidents remains unresolved.
However, U.S. investigators haven't determined who or what was behind the alleged attacks.