The UK Foreign Office has expressed concern over reports that a Hong Kong consulate employee has been detained at the Chinese border.
Media reports said Simon Cheng, who is thought to be from Hong Kong, is believed to have gone missing on 8 August.
An FCO statement said it was “seeking further information from authorities in Guangdong Province and Hong Kong”.
The British embassy in Beijing is providing support to the family.
An FCO spokesperson said: “We are concerned by reports that a member of our team has been detained while returning to Hong Kong from Shenzhen.”
Local outlet HKFP reports that Mr Cheng is a trade and investment officer at the Scottish Development International section of the consulate, and had travelled to a business event in Shenzhen on 8 August via the Lo Wu immigration control point.
His girlfriend told news site HK01 he had planned to travel home by train the same day, but did not return.
Travellers have described heightened security measures at the border between Hong Kong and China, as Beijing looks to curb anti-government protests in Hong Kong which it has called “close to terrorism”.
Recent travellers have reported that everyone passing through the border from Hong Kong into mainland China was subject to police checks on the mainland side, where officers took people’s phones and scrutinised their photos and videos.
Case study: “Ms Chan” is a Hong Konger travelling to mainland China for work, who was forced to delete photos from her phone at the border. Police holding random checks asked her to hand over her phone, which included some WhatsApp conversations with friends about the protests.
“I was so afraid of them checking my phone, so I gave them my old phone. I thought I had deleted all protest photos, but they also checked for protest-related posters and news. After seeing I had these on my phone, the staff immediately called other uniformed staff, took me to another room, and asked about my background, my job, whether I had joined the protests. Another staff member carefully checked my phone’s photo albums to see how many protest-related photos I had.
“I have deleted some protest photos on my iPhone, but I didn’t realise those were moved to the ‘recently deleted’ folder. The officer also checked that. He found I had about a hundred protest photos and asked me to delete them all.
“My observation is that they check two people out of three. The situation is quite severe. None of my friends want to go to mainland China now.”
Hong Kong’s protests, now entering their third month, were sparked by a controversial extradition bill which has since been suspended.
They have grown into a broader movement calling for democratic reform in Hong Kong, and an investigation into alleged police brutality against protesters.
Police put the figure much lower at 128,000, counting only those at an officially sanctioned rally in the city’s Victoria Park.
Some observers believe Beijing’s hardening rhetoric is a sign it is losing patience with the protesters and raises the likelihood of a direct intervention by China.
Analysts say this remains unlikely, despite the thousands of armed police stationed across the border in Shenzhen.
Twitter said it removed 936 accounts it said were being used to “sow political discord in Hong Kong”.
The network said the accounts originated in mainland China and were part of a coordinated attempt to undermine the “legitimacy and political positions of the protest movement”.
Facebook said it had removed “seven Pages, three Groups and five Facebook accounts”.
“They frequently posted about local political news and issues including topics like the ongoing protests in Hong Kong,” said Nathaniel Gleicher, Facebook’s head of cybersecurity policy.
“Although the people behind this activity attempted to conceal their identities, our investigation found links to individuals associated with the Chinese government.”