Britain's Foreign Office says it is "extremely concerned" by reports that an employee at its Hong Kong consulate has been detained in mainland China.
Hong Kong's local news website HK01 says the employee, identified as Simon Cheng, failed to return to the former British colony from the neighboring southern city of Shenzhen on August 9, where he had gone to attend a business meeting.
The Foreign and Commonwealth Office issued a statement says it is providing support to Cheng's family and "seeking further information from authorities in Guangdong province and Hong Kong."
Hong Kong has been gripped by nearly two months of heated and often violent anti-government protests. Beijing was angered when British Foreign Secretary Dominic Raab had a telephone conversation with Hong Kong leader Carrie Lam Friday about the demonstrations earlier this month.
China's foreign ministry issued a statement saying it "solemnly demands" that the British "immediately stop all actions that meddle in Hong Kong affairs and interfere in China's internal affairs."