"I would caution you all to be very skeptical of those officials statements right now. As you should be aware, the investigation continues into what has caused what we have called health attacks on our state dept. employees who have been working in Cuba," Nauert told reporters.
Nauert added that right now there is no known cause of the "health attacks" and no known person or group is believed to be responsible.
In August of 2017, the State Department said nearly two dozen diplomats working at its embassy in Cuba were affected by an incident involving a mysterious audio device. Some of the diplomats suffered permanent hearing loss and possible brain injuries due to a sonic weapon.
In July, media reported that a diplomat at the US consulate in the Chinese city of Guangzhou complained about "abnormal" sounds and pressure. Secretary of State Mike Pompeo said this incident in China was very similar and entirely consistent with the medical indications of the incidents in Cuba.