Hong Kong has begun a mandatory two-week quarantine for anyone arriving from mainland China, in a fresh effort to contain the new coronavirus.
Visitors must isolate themselves in hotel rooms or go to government-run centres, while returning Hong Kong residents must stay inside their homes.
Anyone caught flouting the new rules faces a fine and a prison sentence.
Tens of thousands of travelers queued at the Chinese border city of Shenzhen ahead of the midnight deadline.
Hong Kong has seen 26 confirmed cases of the virus and one person has died. The number of confirmed cases in mainland China stands at more than 31,200, with 717 deaths.
Outside China, 270 cases have been confirmed in at least 25 countries, with one other fatality – in the Philippines.
There was some positive news on Friday when the World Health Organization (WHO) said there had been fewer reported infections in China in the past two days. However, director-general Tedros Adhanom Ghebreyesus cautioned against reading too much into those figures.
“When supply is short, and demand is high then there could be bad practices like hoarding in order to sell them at higher prices,” he warned, urging suppliers to “uphold the protection of humanity” rather than looking to increase profits.
The WHO also released new data from 17,000 patients that suggested 82% had a mild form of the disease, with 15% considered severe cases and 3% critical.