The U.S. State Department issued a health alert after a government employee stationed in China was diagnosed with a mild traumatic brain injury, evoking memories of the series of so-called "sonic attacks" on American diplomats in Cuba.

The U.S. official, who was assigned to the southern city of Guangzhou, reported "subtle and vague, but abnormal, sensations of sound and pressure," the State Department said in an alert Wednesday.

The notification from the department said Washington was not currently aware of any similar situations inside or outside the diplomatic community.

The State Department, which did not link the case in China to any other incident, said anyone in China who experienced "acute auditory or sensory phenomena accompanied by unusual sounds or piercing noises" should move away from the area.