US government employee has been barred from leaving China while visiting for personal reasons, the State Department confirmed. The staffer, from the US Patent and Trademark Office, is under an “exit ban,” and Washington is working with Chinese authorities to resolve the case.

Media reports say the Chinese-American employee was detained in Chengdu in April over alleged threats to national security. Beijing has not provided further details, according to Firstpost.

The incident follows a similar case involving a US banking executive also blocked from leaving China, amid ongoing tensions between the two countries over national security and espionage concerns.