The United States has set up a task force to oversee the response to mystery ailments among its diplomats in Cuba and China, Secretary of State Mike Pompeo said Tuesday.

The State Department has previously said brain injuries suffered by 24 US officials and family members posted in Havana could have been the result of a "health attack," perhaps from an unidentified secret weapon.

Washington has said in the past that Cuban authorities must take responsibility for the safety of US diplomats on their soil, but the Havana government denies any knowledge of an attack.

Last month, another American employee fell ill with similar symptoms in China, reviving fears that a US rival has developed some kind of invisible acoustic or microwave device.

Announcing the task force, however, Pompeo said: "The precise nature of the injuries suffered by the affected personnel, and whether a common cause exists for all cases, has not yet been established."

According to the State Department, the "Health Incidents Response Task Force" will coordinate both the investigation and the treatment of the victims and work with several government and military agencies.

The statement makes no reference to the possibility of a deliberate attack.

But it warns that US diplomats should alert their mission's medical staff "if they note new onset of symptoms that may have begun in association with experiencing unidentified auditory sensations."

"Reported symptoms have included dizziness, headaches, tinnitus, fatigue, cognitive issues, visual problems, ear complaints and hearing loss, and difficulty sleeping," it adds.

US Marines commander at Japan base sacked
Tokyo (AFP) June 5, 2018 –

The commanding officer at a US Marine base on the Japanese island of Okinawa has been fired over a "loss of trust", the US Marines said Tuesday.

A brief statement said Colonel Mark S. Coppess had been relieved of duty as commanding officer of the Futenma base "due to a loss of trust and confidence in his ability to lead his command."

There was no immediate comment or further detail from the Marines on why Coppess had been dismissed, but a US defence official told AFP it had nothing to do with a string of accidents that have plagued military aircraft in Japan.

In February, the commander of the Marines' Japan-based Osprey squadron was fired after several accidents involving the hybrid aircraft.

The most serious, in 2017, involved the crash of an MV-22 Osprey off the east coast of Australia.

The issues involving US military aircraft in Japan have stoked tension over the US military presence in the country.

Okinawa hosts the bulk of some 47,000 US troops based in Japan, and their presence has been a source of friction with residents.

The prefecture was the site of a major World War II battle that was followed by a 27-year US occupation of the island, and it would serve as a launchpad for any American military activity in Asia.