Hong Kong's national security law does not spell "doom and gloom", leader Carrie Lam says, as she tries to calm unease over legislation that critics say could mean the end of freedoms that have underpinned the city's success as a financial hub.
In an illustration of worries about the law, the video app TikTok said it was preparing to leave the Hong Kong market in response to it, and other tech firms said they were suspending processing Hong Kong government requests for user data.
The sweeping legislation that Beijing imposed on the former British colony punishes what China defines as secession, subversion, terrorism and collusion with foreign forces, with up to life in prison.
It came into force at the same time it was made public, just before midnight last Tuesday, with police arresting about 300 people in protests the next day - about 10 of them for suspected violations of it.
"Surely, this is not doom and gloom for Hong Kong," the city's Beijing-backed leader, Carrie Lam, told a regular weekly news conference on Tuesday.
"I'm sure, with the passage of time, and efforts and facts are being laid out, confidence will grow in 'one country, two systems' and in Hong Kong's future."
The legislation has been criticised by Hong Kong democracy activists, as well as countries such as Britain and the United States, for undermining freedoms guaranteed under a "one country, two systems" formula agreed when Hong Kong return to Chinese rule in 1997.
Hong Kong and Chinese government officials have said the law, which gives mainland security agencies an enforcement presence in the city for the first time, was vital to plug holes in national security defences, exposed by the city's failure to pass such legislation itself as required under its mini-constitution, the Basic Law.
Critics say its aim is to stamp out a pro-democracy movement that brought months of protests, at times violent, to the city last year.
Lam said cases involving a new mainland agency that would be set up in Hong Kong under the law would be rare but nevertheless, national security was a "red line" that should not be crossed.
Despite such assurances, the law has had a chilling effect.
Pro-democracy activists such as Joshua Wong disbanded their organisations while others have left. Many shops have removed protest-related products and decorations and public libraries have removed some books seen as supportive of the democracy movement. Canada has suspended an extradition treaty with Hong Kong.
TikTok, a video app owned by China-based ByteDance, which has said in the past its user data is not stored in China, said it would exit the Hong Kong market within days.
Facebook, which also owns WhatsApp and Instagram, Google and Twitter suspended processing government requests for user data in Hong Kong.
But Lam said she had not noticed widespread fears and the law would restore the city's status as one of the safest in the world after the violent pro-democracy protests last year.
Late on Monday, Hong Kong released additional details of the law, saying security forces had overriding authority to enter and search properties for evidence and to stop people from leaving the city.
Lam, asked about media freedom, said if reporters could guarantee they would not breach the new law, she could guarantee they would be allowed to report freely.