The United States has pulled two more of its workers out of Cuba and are testing them for possible brain injury, three U.S. officials told The Associated Press on Friday, amid concerns they may have been affected by the mysterious health incidents harming U.S. diplomats in Cuba and China.The two individuals are considered “potentially new cases” but have not yet been “medically confirmed,” a State Department official said. 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 new potential cases from a U.S. consulate in China.

READ MORE: More American diplomats in China hit with mystery health issues, U.S. says 

The officials were not authorized to comment publicly on the matter and spoke on condition of anonymity.So far there are 24 confirmed patients affected by the bizarre incidents, first disclosed last year, that 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.Until Friday, the most recent suspicious incidents disclosed by the U.S. had been in August 2017, leading many to suspect they had stopped.

READ MORE: Sonic attacks in China? U.S. issues warning of similar incident that injured Canadians in Cuba

The two new individuals removed from Cuba were medically evaluated in just the past few weeks, two officials said.The confirmed Cuba patients have been found to have a range of symptoms and diagnoses including mild traumatic brain injury, also known as concussions. Unexplained sounds and vibrations that accompanied the symptoms initially led investigators to suspect a sonic weapon, although an interim FBI report in January said no evidence had been uncovered that sound waves could have damaged the Americans’ health, The Associated Press reported.WATCH: Canada pulls families of diplomatic staff from Cuba after mysterious health symptoms
Click to play video: 'Canada pulls families of diplomatic staff from Cuba after mysterious health symptoms' Canada pulls families of diplomatic staff from Cuba after mysterious health symptoms
Canada pulls families of diplomatic staff from Cuba after mysterious health symptoms – Apr 17, 2018
The potential new cases come as 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 department has sent a medical team to Guangzhou to offer medical screenings to all American government workers and family members who want them. The team arrived late last week and has started evaluating Americans.Of the roughly 170 American consulate staffers and family members in Guangzhou, about 150 sought the offered preliminary medical examinations, according to officials familiar with the process. The officials stressed that some of them may not have experienced any symptoms and were having the tests done protectively. Although the vast majority of them were cleared, eight people were referred to the University of Pennsylvania for additional testing, the officials said.WATCH: Canada has no clue what made Cuba diplomats sick
Click to play video: 'Canada has no clue what made Cuba diplomats sick' Canada has no clue what made Cuba diplomats sick
Canada has no clue what made Cuba diplomats sick – Jan 10, 2018
The U.S. diplomatic presence in China is large with representatives from 33 different federal agencies employed at the embassy in Beijing and the five consulates on the mainland: Chengdu, Guangzhou, Shanghai, Shenyang and Wuhan. As of May 2017, when the State Department inspector general’s office conducted its last inspection of the missions in China, almost 900 Americans worked at them, including 168 who were hired locally.