Hong Kong's legislature has unanimously passed a new national security law with tough penalties, including life imprisonment for treason and insurrection.
The law, which the United States, Britain and the European Union have warned could further curtail freedoms in Hong Kong, was fast-tracked through the city's rubber-stamp legislature.
"Today is a historic moment for Hong Kong," city leader John Lee said after the vote, adding the law would come into effect on 23 March.
Commonly referred to as Article 23, the homegrown legislation will work in tandem with the national security law imposed by Beijing in 2020 in the wake of huge and at times violent democracy protests.
The new law punishes dozens of new and revamped offences under five categories: treason, insurrection, theft of state secrets and espionage, sabotage endangering national security, and external interference.
Mr Lee had said the law was needed to plug the legislative gaps left by Beijing's law - which targets secession, subversion, terrorism and collusion with foreign forces.
He had also repeatedly cited Hong Kong's "constitutional responsibility" to create it as required by the Basic Law, the city's mini-constitution since its handover from Britain to China in 1997.
The law "will allow Hong Kong to effectively prevent, prohibit and punish espionage activities, plots and traps set up by foreign intelligence units, infiltration and sabotage carried out by hostile forces," Mr Lee has said.
He added that it would also "effectively prevent black-clad violence and color revolution", a reference to the democracy protests which kicked off in 2019.
One of the last-minute amendments added last week by the government empowers Mr Lee and his cabinet to create new offences - to account for "unforeseen circumstances" - punishable by up to seven years in prison.
'An effective lock'
Sanctioned by the US for his oversight of the protests in his role as security chief, Mr Lee has called the law "an effective lock to prevent burglars" as authorities seek to combat "threats posed by external forces and local terrorism".
Penalties run up to life in prison for sabotage endangering national security, treason and insurrection; 20 years for espionage and sabotage; and 14 years for external interference.
It has also expanded the British colonial-era offence of "sedition" to include inciting hatred against China's Communist leadership, with an aggravated sentence up to ten years in jail.
And, as with its 2020 predecessor, some offences committed outside Hong Kong will fall under its jurisdiction.
As part of the 1997 handover from Britain, Hong Kong was guaranteed certain freedoms - as well as judicial and legislative autonomy - for 50 years in a deal known as "One country, two systems".
This has helped cement the city's status as a world-class business hub, bolstered by a reliable judiciary and political freedoms distinct from the mainland.
Britain's foreign minister David Cameron said the new law "undermines Hong Kong's implementation of binding international obligations including the Sino-British Joint Declaration and the International Covenant on Civil and Political Rights".
US State Department deputy spokesperson Vedant Patel said it has the potential to accelerate the closing of a once open society, adding that the United States is analysing the potential risks to US citizens and American interests.
Mr Patel told reporters that the crimes outlined in the legislation are poorly defined and incredibly vague.
