Cuba's Foreign Ministry confirmed Sunday that a female U.S. diplomat fell ill last month after hearing "undefined sounds" in her Havana residence.

The May 27 incident marks the latest mysterious health incident involving a U.S. official in the country. Some two dozen American diplomats have fallen ill as a result of the episodes, which were first made public last year.

Cuba's Foreign Ministry said that the U.S. Embassy had informed it of the woman's illness on May 29. Cuba said it sent investigators to the home who found no potential source of a sound and were not granted access to the official.

'SONIC ATTACKS' EYED IN CUBA, CHINA AS MORE US DIPLOMATS FALL ILL

U.S. officials said Friday that they had pulled two workers from Cuba and were testing them for possible brain injury. There was no immediate explanation of why the Cuban statement referred only to one official.

The two individuals were considered "potentially new cases" but have not yet been "medically confirmed," a State Department official told The Associated Press. Two other officials said the individuals have been brought for testing to the University of Pennsylvania, where doctors have been evaluating, treating and studying Americans affected in Cuba last year as well as almost 10 new possible cases from a U.S. consulate in China.

The officials weren't authorized to comment publicly and requested anonymity.

If confirmed by doctors to have the same condition, the two individuals would mark the 25th and 26th confirmed patients from the bizarre incidents in Cuba that were first disclosed last year and have been deemed "specific attacks" by the U.S. government. The United States has said it doesn't know who is behind it, but has argued Cuba is responsible for protecting all diplomats on its soil.

Cuba has denied any involvement in or knowledge of what may have caused the injuries.

"Cuba has reaffirmed publicly and officially its willingness to cooperate in earnest in the joint search for answers, the elucidation and solution to the alleged facts," the Cuban statement said Sunday. "The Ministry of Foreign Affairs reiterates that no evidence whatsoever has been presented of the alleged incidents and maintains its unwavering commitment to cooperate with the authorities from the United States to achieve the elucidation of this situation and the best medical attention to the persons concerned."

Meantime, the U.S. has being issuing health alerts to Americans in China after a worker at the U.S. Consulate in Guangzhou reported symptoms and strange sounds and was flown to the U.S. That worker was then medically confirmed to have "suffered a medical incident consistent with what other U.S. government personnel experienced in Havana, Cuba," the State Department has said.

The Associated Press contributed to this report.