The Canadian Consulate in Hong Kong said Friday that local staff would not be allowed to leave the city on official business, following the detention of a British Consulate worker in mainland China.

It didn't say whether the travel restriction was related to the detention of Simon Cheng Man-kit, who went missing two weeks ago after he went on a business trip from Hong Kong's high-speed rail terminal to Shenzhen, a mainland city just across the border from the semiautonomous territory.

"At present, locally engaged staff will not undertake official business travel outside of Hong Kong," the Canadian Consulate said in a statement.

The Chinese government's announcement this week that Cheng had been detained has stoked tensions in Hong Kong, which has been gripped by more than two months of anti-government protests sparked by outrage over proposed legislation that would have allowed some criminal suspects to be sent to the mainland for trial.

Simon Cheng (second from left), a staffer at the British Consulate in Hong Kong, has been given 15 days of "administrative detention" in China for "soliciting prostitutes." (Wilson Li/The Associated Press)

The head of the cabin crew union for Cathay Dragon, a Hong Kong-based regional airline, said Friday that she had been fired in retaliation for supporting the protests.

Rebecca Sy said the carrier dismissed her without giving a reason, but that the firing came after she was pulled from a flight at short notice and asked by an airline representative to confirm that a screenshot from Facebook was from her account.

The union said in a statement the firing is a "blatant suppression and retaliation on her participation in the anti-extradition bill movement and her actions to mobilize her colleagues to participate as a trade union leader."

Cathay Dragon is owned by Hong Kong's main carrier, Cathay Pacific. It did not respond to a request for comment.

The missing worker, Cheng, had worked for the British Consulate since December 2017 as an international trade and investment officer for the Scottish government. He and other local staff at consulates and embassies support diplomats but don't have diplomatic passports themselves.

Detained for 'soliciting prostitutes'

China said this week Cheng had been placed in administrative detention for 15 days for violating public order regulations. It did not elaborate.

The Global Times, a Communist Party-owned nationalistic tabloid, reported Wednesday that Chen was detained for "soliciting prostitutes." Police in Shenzhen did not respond to requests for confirmation of the report.

China often uses public order charges against political targets and has sometimes used the charge of soliciting prostitution. Ou Shaokun, an anti-corruption activist, alleged in 2015 that he was framed by authorities in southern Hunan province who said they found him in a hotel room with a prostitute.

The Canadian government also updated its travel advice for China on Thursday to warn of stepped up border checks on phones.

"Increased screening of travellers' digital devices has been reported at border crossings between mainland China and Hong Kong," the advisory said.

There have been increasing reports that Chinese immigration officers are inspecting phones for photos related to the Hong Kong protests.