Washington: The US State Department has brought a group of diplomats home from Guangzhou, China, over concerns they were suffering from a mysterious malady that resembles a brain injury that already has affected US personnel in Cuba, its spokeswoman said on Wednesday.

After confirming one government employee had "suffered a medical incident" in the southern Chinese city, the department deployed a team to screen employees and family members at its consulate there, spokeswoman Heather Nauert said in a statement.

Security workers guard a construction site of the US Consulate compound in Guangzhou in southern China's Guangdong province. Credit:AP

"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 said.

"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," she said.