More than 20 US officials posted in Havana have suffered injuries consistent with brain injury, which the US State Department has said could have been the result of a "health attack", from an unidentified secret weapon, possibly an acoustic or microwave device.
The two latest staff members from the Cuba embassy could be "potentially new cases" but are yet to be "medically confirmed", a US State Department official told the Associated Press news agency.
A State Department spokesman said they were being tested for brain injuries.
The Penn team, which published its Cuba findings February in the Journal of the American Medical Association, was not able to prove what caused the symptoms in those patients.
If confirmed by doctors to have the same condition, the two individuals would mark the 25th and 26th confirmed patients from the weird incidents in Cuba that were first disclosed previous year and have been deemed "specific attacks" by the USA government.
Cuba released details Sunday on the latest mysterious health incident involving a USA diplomat in the country, saying that Cuban officials learned of the episode late last month when the US said that an embassy official felt ill after hearing "undefined sounds" in her home in Havana.
The bulk of cases took place between the end of 2016 and the summer of 2017, with symptoms including hearing loss, cognitive impairment, vertigo, insomnia or vision problems.
The incident rattled U.S. -Cuba relations, but the occurrence of similar symptoms in China has raised suspicions about whether China, Russia, or another country might be to blame.
Hua Chunying, spokesperson of the Ministry of Foreign Relations, recalled that from the first report on the mysterious sonic affection, studies were carried on and conclusions were presented to USA authorities.
Last month, the US State Department urged its staff in China to alert them to any abnormal hearing or vision issues after an employee reported mystery symptoms.
A security person walks outside the US consulate building in Guangzhou in south China's Guangdong province, Thursday, June 7. The AP reported that out of the approximately 170 American staffers in the consulate, 150 have undergone the examinations.