"We can not at this time connect it with what happened in Havana, but we are investigating all possibilities", a United States embassy official said.
The health alert issued Wednesday warned USA citizens to be vigilant. The report comes after multiple US and Canadian nationals suffered from what the USA government called "health attacks" in Cuba.
The US has disclosed that 24 diplomats and their relatives had fallen victim to an unsolved mysterious attack in Cuba that left them with injuries resembling brain trauma.
"A U.S. government employee in China recently reported subtle and vague, but abnormal, sensations of sound and pressure", the notice said.
Wednesday's alert said the US government does not know the cause of the reported symptoms and has not received similar reports in other parts of China, but that it is taking the report seriously.
Though some experts expressed doubt when the possibility of a sonic attack in Cuba was first raised, the State Department points to a study by independent medical personnel published earlier this year in The Journal of the American Medical Association.
China's Foreign Ministry did not immediately respond to a request for comment.
"The Department is taking this incident very seriously and is working to determine the cause and impact of the incident", Lee said in an email.
The department also warned against attempting to locate the source of any unusual sounds.
Speaking in congress on Wednesday, US Secretary of State Mike Pompeo said the victims in both instances suffered similar symptoms.
Officials initially suspected the Americans had been targeted by an acoustic weapon, but media reports have suggested that the Federal Bureau of Investigation has been unable to verify any evidence to support that theory. In almost all cases, the ailments were preceded by some sort of "acoustic element", such as a "high-pitched beam of sound" or a "baffling sensation akin to driving with the windows partially open in a auto". "Instead, move to a location where the sounds are not present", it says, urging people with medical problems to consult a doctor.
The report comes as the U.S.is seeking to negotiate concessions from China to narrow its trade deficit.
Of the 21 medically confirmed United States victims, some have permanent hearing loss or concussions, while others suffered nausea, headaches and ear-ringing.