U.S. officials are checking “a number of” State Department personnel in China who may have suffered from the same kind of mysterious attack that caused brain injuries to two dozen Americans in Cuba, the department’s top spokeswoman announced.

“The medical screenings are ongoing for any personnel who have noted concerning symptoms or wanted baseline screening,” State Department spokeswoman Heather Nauert said in a Wednesday evening statement. “As a result of the screening process so far, the Department has sent a number of individuals for further evaluation and a comprehensive assessment of their symptoms and findings in the United States.”

Nauert’s statement followed a report that the State Department “evacuated at least two more Americans from China on Wednesday,” according to the New York Times. That revelation follows Secretary of State Mike Pompeo’s announcement that an official in China had been stricken with ailments “consistent with what happened to American officers” in Cuba. One of the officials evacuated complained that the State Department didn’t alert the team on the ground immediately upon learning of the first incident.

“In an email sent to the entire staff of the consulate, he complained that the first employee was evacuated in April, but that no one was told of the health concerns until a month later — after doctors in the United States had found evidence of brain trauma,” the New York Times reported.

Nauert implicitly pushed back against that criticism, noting that Pompeo mobilized a medical team “as soon as” the department linked the incident in China to the attacks in Cuba.

“The State Department has been and will continue to be diligent and transparent in its response to our employees' concerns,” she said. “US medical professionals will continue to conduct full evaluations to determine the cause of the reported symptoms and whether the findings are consistent with those noted in previously affected government personnel or possibly completely unrelated.”

The cause of the incidents remains a mystery, but the emergence of symptoms in both China and Cuba raises fears of a far-reaching threat to American diplomats.

“The public evidence we have is consistent with two theories that are diametrically opposed: One is the Chinese are behind this, and the other is somebody is trying to frame the Chinese,” a Senate Republican aide told the Washington Examiner. “Are the Russians capable of screwing with our diplomats in Cuba and China in order to paint the Cubans or the Chinese? Of course they are. But are the Chinese capable of screwing with our diplomats in Cuba and [China] because they don't like us? Of course they are.”