U.S. citizens living in China received a second alert on Friday over the unexplained health issues that prompted the evacuation of a number of government employees working at a consulate in the southern city of Guangzhou.

The alert, the second in just two weeks, urged Americans to seek medical help in the event they suffered any “unusual, unexplained physical symptoms or events, auditory or sensory phenomena, or other health concerns.”

The comes just days after the State Department announced that “a number of individuals” had been sent back to the United States after they suffered illnesses similar to those experienced by government personnel in Cuba last year.

Spokeswoman Heather Nauert said Wednesday that medical screenings were ongoing for “any personnel who have noted concerning symptoms or wanted baseline screening.”

The tests were prompted after a previous case in the Guangzhou consulate was disclosed last month.

The incidents have raised fears the unexplained issues that started in Cuba in 2016 have expanded to other countries. China says it has uncovered no information that could point to a cause.

In October, at least 24 Americans at the U.S. Embassy in Cuba complained of unexplained illnesses that the State Department at the time called “health attacks.”

The employees reported hearing loud, grating noises before experiencing hearing loss, dizziness, headache, fatigue, cognitive issues and difficulty sleeping. Cuba has maintained that it had no involvement or knowledge of any such attacks.

Friday’s alert called for people to be attentive to the same symptoms experienced by employees in Cuba. It urged them “not to attempt to locate the source of any unidentified auditory sensation. Instead, move to a different location.”

Asked about the latest incidents, Chinese Foreign Ministry spokeswoman Hua Chunying said Thursday that the U.S. had not formally raised the matter with Beijing.

"If the U.S. makes formal contact with us, China will continue necessary investigations in an earnest and responsible manner and maintain close communication and cooperation with the U.S.," Hua said at a regularly scheduled news conference.

People working in The Canton Place complex, a few kilometers (miles) from the consulate, said Thursday they were just hearing about the incidents, reflecting a lack of coverage in China's entirely state-controlled media.

Aled Williams, a British teacher at a kindergarten, said Thursday that the reports sounded "sci-fi-ish."

"Hard to get my head around how it works," he said. "Better watch myself."

Linda Chen, who runs a coffee shop in the area, said she was mystified as to why only certain people seemed to have been affected in an area known for its comfort and safety.

"For me I feel it's very strange. But I don't feel that there's something to be very afraid of because it's probably a very special case," Chen said.

Fox News’ Paulina Dedaj and the Associated Press contributed to this report.