A United States Government employee in southern China has reported suffering from "abnormal" sounds and pressure leading to a mild brain injury, the US embassy said — recalling similar experiences among American diplomats in Cuba.

Key points: The unnamed worker was sent to the United States for further evaluation

The unnamed worker was sent to the United States for further evaluation Last year, 21 victims in Cuba suffered a range of ailments after hearing an unusual sound

Last year, 21 victims in Cuba suffered a range of ailments after hearing an unusual sound The Chinese Government has told the embassy it is also investigating

In an emailed notice to American citizens in China, the department said it was not currently known what caused the symptoms in the city of Guangzhou, where an American consulate is located.

"A US Government employee in China recently reported subtle and vague, but abnormal, sensations of sound and pressure," the notice said.

"The US Government is taking these reports seriously and has informed its official staff in China of this event."

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 US 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.

It added the Chinese Government told the embassy it is 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 US embassy official told Reuters.

China's Foreign Ministry and National Health Commission did not immediately respond to faxed questions about the report.

Similarities to Cuban 'sonic attacks'

Last year in Cuba, the US reported that some of its personnel and family members experienced a range of ailments, some after hearing an unusual sound.

For most the symptoms occurred around May 2017, but they were first reported in late 2016.

Of the 21 medically confirmed US victims, some have permanent hearing loss or concussions, while others suffered nausea, headaches and ear-ringing.

Some are struggling with concentration or common word recall, The Associated Press has reported.

Though Cuban officials dismissed the idea of acoustic strikes as "science fiction" and accused Washington of slander.

Some felt vibrations or heard loud sounds mysteriously audible in only parts of rooms, and others heard nothing.

The still-unexplained incidents sparked a rift in US-Cuban relations, while investigators have chased theories including a sonic attack, electromagnetic weapon or flawed spying device.

The cause of those incidents remains unresolved.

ABC/Wires