The warning, issued on May 23, has prompted comparisons to similar phenomena that were reported by US diplomatic personnel in Cuba in 2016. Last September, Washington recalled the majority of its personnel from its embassy in Havana and issued a travel warning advising its citizens to stay away from the island. These actions were taken in response to allegations made by the United States that at least 21 of its diplomatic and support staff stationed in Cuba suffered from sudden and unexplained loss of hearings, causing them to be diagnosed with brain injuries. In April, the Canadian embassy evacuated all family members of its personnel stationed in Havana, over similar health concerns.

Now a similar warning has been issued by the US Department of State for its staff stationed in China. In a statement, the Department said that a member of staff at its consulate in the Chinese city of Guangzhou reported experiencing “subtle and vague, but abnormal, sensations of sound and pressure”. The unnamed individual reportedly suffered these physical symptoms between late 2017 and April 2018, said the statement. At that time, the individual was flown back to the US where they eventually were diagnosed with “mild traumatic brain injury”. The statement went on to state that the cause of these symptoms remains unknown, and that the US government has no information about other such incidents affecting Americans in China.

Late on Wednesday, however, speaking before the Committee on Foreign Affairs of the US House of Representatives, US Secretary of State Mike Pompeo said that the incident in China was “medically similar” to the 2016 incidents in Cuba. Some US government sources have blamed these medical symptoms on unspecified “sonic weapon attacks” from a foreign country, aimed at US diplomatic facilities.  But Washington has so far refrained from accusing China of having a role in such attacks, either in Cuba or in China itself. Pompeo said on Wednesday that Washington had dispatched a medical team to Guangzhou to inspect American diplomats stationed there. The Chinese government said yesterday that it was probing the incident “in a very responsible manner” and “would protect the lawful rights and interest of foreigners in China”. However, China’s Minister of Foreign Affairs, Wang Yi, warned that the case in Guangzhou should not be “magnified, complicated or even politicized” by Washington.