Facebook and its messaging app WhatsApp said in separate statements Monday that they would freeze the review of government requests for user data in Hong Kong, "pending further assessment of the National Security Law, including formal human rights due diligence and consultations with worldwide human rights experts".
The decision by WhatsApp comes after China fast-tracked legislation that allows local authorities to supervise and regulate the city's previously unrestricted internet.
Some Hong Kong residents said they were reviewing their previous posts on social media related to pro-democracy protests and the security law, and proactively deleting ones they thought would be viewed as sensitive.
Tong, who was hospitalized after the incident and appeared at the West Kowloon Magistrates Court in a wheelchair, was allegedly a carrying a "Liberate Hong Kong" banner at the time - now grounds for inciting succession under the new law, prosecutors said.
Hong Kong returned to China on July 1, 1997, under a "one country, two systems" formula guaranteeing wide-ranging autonomy and freedoms not enjoyed on the mainland, including an independent judiciary.
The vaguely defined rules broaden the power of officials to investigate, prosecute and punish both foreign nationals and citizens for anything deemed to be promoting secession or subversion of the government, like "inciting hatred" of the central Chinese authority.
In Hong Kong's public libraries, books by pro-democracy figures have been pulled from the shelves, including those authored by prominent pro-democracy activist Joshua Wong and politician Tanya Chan.
Amid a diplomatic crisis triggered by China's clampdown on Hong Kong, Chinese officials harshly condemned retaliatory moves taken by the United Kingdom and Canada.
The law also obliges "foreign and Taiwan" agents and political organizations linked to an investigation into a potential national security breach to disclose information to the authorities.
Hong Kong's role "as a global hub was built on that foundation", he added.
Hong Kong's government issued the details of Article 43 in the city's national security law on Monday night, which outlines the measures that the police force can take to implement the legislation in the city. The national security law was formally approved by Beijing last week, and has already yielded its first prosecution.