People in Hong Kong face the possibility of life behind bars for breaking a controversial new security law imposed by China.
Details of the law, which criminalises secession, subversion and collusion with foreign forces, were published after it had come into force.
Critics say the new law effectively curtails protest and freedom of speech.
It was brought in by Beijing following increasing unrest and a widening pro-democracy movement.
Hong Kong's leader, Carrie Lam, defended the law, saying it filled a "gaping hole" in national security. Earlier, the Beijing-backed politician admitted she had not seen the draft.
The UK, EU and Nato have all expressed concern and anger, while pro-democracy groups have started to disband.
What do we know about the law?
Full details only emerged after it had come into effect at about 11pm local time on Tuesday.
They include that:
- Crimes of secession, subversion, terrorism and collusion with foreign forces are punishable by a minimum sentence of 10 years, with the maximum being life
- Inciting hatred of the central government and Hong Kong's regional government are now offences under Article 29
- Damaging public transport facilities can be considered terrorism
- Those found guilty will not be allowed to stand for public office
- Beijing will establish a new security office in Hong Kong, with its own law enforcement personnel - neither of which would come under the local authority's jurisdiction
- Hong Kong's chief executive can appoint judges in national security cases and the justice secretary can decide whether or not there is a jury
- Decisions made by the national security commission, set up by local authorities, cannot be challenged legally
- China also says it will take over prosecution in cases which are considered "very serious", while some trials will be heard behind closed doors.
- People suspected of breaking the law can be wire-tapped and put under surveillance
- Management of foreign non-governmental organisations and news agencies will be strengthened
- The law will also apply to non-permanent residents
What has the reaction been?
The reaction began the moment the law - which was first announced six weeks ago - was signed by China's President Xi Jingping.
Pro-democracy activists in Hong Kong began to quit immediately, fearful of the new law, and the punishment it allows.
Joshua Wong, secretary-general and founding member of pro-democracy group Demosisto, warned the city would "turn into a secret police state".
The head of human rights group Amnesty International's China team, Joshua Rosenzweig, accused Beijing of aiming to "govern Hong Kong through fear from this point forward".
The move also provoked international reaction, with the UK's Foreign Secretary, Dominic Raab, saying China had broken the promises it had made to the people of Hong Kong under the terms of the 1997 handover.
That agreement enshrined the "one country, two systems" principle in a document called the Basic Law - Hong Kong's mini constitution - for 50 years.
Basic Law protects rights such as freedom of assembly and freedom of speech - neither of which exist in mainland China - and also sets out the structure of governance for the territory.
Julian Braithwaite, Britain's ambassador to the United Nations in Geneva, told the UN Human Rights Council that the law "has clear implications for human rights".
Braithwaite, speaking on behalf of 27 nations, urged China to reconsider.