HONG KONG — A trade officer at the British Consulate in Hong Kong went missing after crossing into mainland China this month, raising fears that the authorities might be targeting travelers suspected of supporting the protest movement.
The officer, Cheng Man Kit, who also goes by Simon, traveled to Shenzhen, the city immediately over the border from Hong Kong, to attend a business conference. But he did not return to work on Aug. 9 as planned.
“We are extremely concerned by reports that a member of our team has been detained returning to Hong Kong from Shenzhen,” Britain’s Foreign and Commonwealth Office said in an emailed statement.
The foreign office said it was providing support to Mr. Cheng’s family and seeking further information from the authorities in Hong Kong and in China’s Guangdong Province, which includes Shenzhen.
Mr. Cheng, a Hong Kong resident, worked for the consulate’s branch of Scottish Development International, a trade and investment promotion office, according to his Facebook biography and a friend.
He holds a British national overseas passport, which entitles him to consular representation. China does not recognize the status, created for Hong Kong residents before the transfer of city to Chinese control in 1997.
HK01, an online Hong Kong news organization that first reported his disappearance, said that Mr. Cheng had traveled to Shenzhen on Aug. 8. He texted his girlfriend later that night as he was about return to Hong Kong aboard the recently opened high-speed railway that links to the territory to the mainland, the report said.
It was not immediately clear why Mr. Cheng would have been detained, though HK01 reported that he was being held in administrative detention, which by law can last for 15 days.
Chinese border officers have stepped up checks on those crossing the border from Hong Kong. They have begun routinely searching the phones of people who enter the mainland from Hong Kong, apparently to identify those sympathetic to the protest movement and to prevent photographs or other information about the demonstrations from spreading to the mainland.