HONG KONG — The family of a man who works for the British consulate in Hong Kong say they "feel helpless" as the Chinese government confirmed it has detained him.
China's Foreign Ministry spokesman Geng Shuang said on Wednesday that the worker, who has been identified as Simon Cheng Man-Kit, was detained in the border city of Shenzhen.
Shuang told a press briefing that Cheng will be held for 15 days by Shenzhen police but didn't specify what law he is suspected of violating. He added that Cheng is not a British citizen but both a citizen of Hong Kong and China, making the issue "entirely China's internal affair."
"We have made representations so that the British side will stop inciting more problems and stop interfering in China’s internal affairs," Shuang said.
Cheng's family said on Wednesday that they had received no information about why he had been detained or how long he would be held.
"We feel very helpless, and are worried sick about Simon," his family said in a statement on Facebook.
Pro-democracy protesters held a "Save Simon Cheng" event outside the British Consulate on Wednesday afternoon, local time, to highlight his case.
His supporters also posted a petition online calling on the U.K. government to "mobilise all efforts to save Simon."
Max Chung, who organized the petition, told NBC News that detention of his friend who was working for the British government is "disgraceful." He said Cheng is smart enough to handle any special requirements imposed on his travel to China.
"I have no idea why they would want to detain him," he said. "Why he was captured [is what] we really want to know."
The U.K. Foreign Office said on Tuesday that its employee was detained while attempting to return to Hong Kong from Shenzhen. Cheng works for the Scottish Development International unit with the consulate.
“We are aware of this incident and we are concerned for Mr Cheng’s welfare," the Scottish government said in a statement Tuesday, adding that officials were in contact with authorities in both China and Hong Kong.
Cheng had been visiting China since Aug. 8 for a business trip, his family said. He had last sent messages to his girlfriend the same day, just before passing through customs to return to the territory.
Cheng's detention comes amid public tensions between the semi-autonomous territory of Hong Kong and mainland China.
Hong Kongers have been taking to the streets since June in a peaceful retaliation to a controversial extradition bill that would allow suspected criminals to be handed over to China. Protests have featured increasing levels of violence in recent weeks, including clashes with police, as demonstrators call for greater democratic freedoms and the resignation of the territory's chief executive Carrie Lam.
Hong Kong is a former British colony and although it became a special administrative region of China in 1997, the territory's 7 million residents can freely surf the internet and participate in public protests, unlike those living in the mainland.
But there is widespread fear those rights and freedoms are being eroded under Beijing's rule.
On Tuesday, Lam announced she was launching an investigation into complaints of police tactics and violence during the protests while reiterating that the controversial extradition bill "is dead."
"There is no plan, there is no plan to revive this bill, especially in light of the public concerns," she said at a press conference.
These measures were not enough to appease protesters.
Thousands took part in a peaceful sit-in at Yuen Long MTR train station Wednesday evening local time, marking a month since pro-democracy demonstrators were targeted at the site by masked assailants.
They also launched a social media campaign, asking supporters to share selfies with their right eye covered in solidarity of a volunteer nurse who was injured in a demonstration that turned violent earlier this month, and also reflecting people's fear of expression.