Hong Kong police have launched a hotline inviting people to report suspected breaches of the SAR's national security law.
In posts on social media on Thursday morning, the force said people can send tips anonymously by email or SMS, as well as one communication app, WeChat.
In a post on Facebook, the force said the hotline was being set up by the police's national security department to accept non-emergency reports on national security matters in the form of information, photographs, audio or video. The force said it will not answer phone calls.
Police stressed that they would not collect personal information on those who use the hotline.
When news of the hotline emerged last week, the move was condemned by pro-democracy campaigners, with warnings that it would spread distrust in the SAR.
But most comments on the police's Facebook post on Thursday morning were positive, with people saying they support the force.
Some said they would report people who eat at "yellow" restaurants deemed to be pro-democracy, and others said they would tip the police off about "yellow" judges.
The force also posted details of the hotline on Twitter, accompanied with various hashtags including #SaveHK, #WeCanHelp and #YouCanHelp. Early comments were predominantly negative, however, several involving the word "gestapo".