The U.S. State Department is warning U.S. citizens in China that a government employee reported unusual “sensations of sound and pressure” and was later diagnosed with a mild traumatic brain injury — a case that recalls a wave of so-called “sonic attacks” on U.S. diplomats in Cuba.

A health alert sent Wednesday said a U.S. government employee assigned to the southern Chinese city of Guangzhou reported “subtle and vague, but abnormal, sensations of sound and pressure.”…

Though the State Department has not linked this case to any other incident, news of unusual symptoms hitting U.S. government employees abroad will no doubt draw comparison to a rash of incidents with U.S. and Canadian diplomats working in Cuba.