Hong Kong's new national security law came into force on Saturday, putting into immediate effect tough penalties of up to life imprisonment for crimes, including treason and insurrection.
The law — commonly referred to as Article 23 — targets five categories of national security crimes, and was swiftly passed by Hong Kong's opposition-free legislature on Tuesday.
The United States, the European Union, Japan and Britain have been among the law's strongest critics, with U.K. Foreign Minister David Cameron saying it would "further damage the rights and freedoms" of those in the city.