“We are basically seeing the Hong Kong government trying to slam shut the really last vestiges of room for criticizing it,” said Kevin Yam, one of 13 overseas pro-democracy activists accused of national security offenses by Hong Kong authorities.

When Britain returned Hong Kong to Chinese rule in 1997, Beijing assured the former colonial power that civil liberties in the city would be preserved.

On Saturday, Hong Kong enacted a measure that critics charge will further stifle free expression in a city that until recently was known for its freewheeling style, aggressive media and politically active populace.

The bill, called the Safeguarding National Security Ordinance but also referred to as the Article 23 law, took effect following unanimous approval earlier this week by Hong Kong’s opposition-free legislature, where it was deliberated over and passed in a record 11 days.

Article 23 is designed to supplement an earlier national security law Beijing imposed on Hong Kong in 2020, one that critics say supercharged the erosion of civil liberties here.