China has failed to keep its promise to the world pertaining to Hong Kong's 1997 reversion to Chinese rule from Britain, Defense Minister Taro Kono said, calling the latest move a "unilateral attempt to change the status quo".
Earlier on Tuesday, a spokesman for Taiwan's Executive Yuan warned Taiwanese travelers "to be careful of the risk that could emerge going to Hong Kong after the enactment of the national security laws".
"The future of "one country, two systems" is extremely important to our country that has close economic relations and people-to-people exchanges with Hong Kong", Suga said, adding Tokyo will work with other nations in urging Beijing to deal with the matter "appropriately".
For about a year, demonstrations have taken place in Hong Kong over recent moves that those in the territory say are steps to ending China's longstanding "one country, two systems" arrangement with Hong Kong.
Analysts said that even without knowing details, the security law radically restructures the relationship between Beijing and Hong Kong.
"After much internal deliberation, we have chose to disband and cease all operation as a group given the circumstances", Demosisto said on Twitter.
"With sweeping powers and ill-defined law, the city will turn into a #secretpolicestate".
What it says: The law defines crimes such as terrorism and sedition broadly, but mandates harsh sentences - in many cases life imprisonment - for those found to have committed them.
The law bypassed Hong Kong's fractious legislature and comes into effect on Tuesday evening, according to the city's current leader Carrie Lam.
A study by the Hong Kong Public Opinion Research Institute showed that 57% of the public opposed the law.
Activists have called for huge demonstrations against the law, coinciding with the 1 July handover celebration. Beijing condemned those protests as an attempt to permanently split Hong Kong away from China.
"It will throttle the city's rule of law, presenting a major confrontation between what passes for law in China and the common law system in Hong Kong, which has allowed the city to function as one of most important financial hubs in Asia.
This would be a grave step", British Foreign Secretary Dominic Raab said.
"To target the US's above wrongful actions, China has made a decision to impose visa restrictions against American individuals who have behaved egregiously on matters concerning Hong Kong", Zhao said. It follows months of anti-government protests in Hong Kong past year that at times descended into violence. Hong Kong's mini-constitution, the Basic Law, and its decades of independent judicial rulings protecting civil rights were to take precedence over Beijing's governance until at least 2047.
On the mainland, national security laws are routinely used to jail critics, especially for the vague offence of "subversion".
While Beijing announced its plan to introduce the law at the end of May, the legislative process was carried out behind closed doors.
Millions took to the streets a year ago while a smaller hard core of protesters frequently battled police in often violent confrontations that saw more than 9,000 arrested.
However many are also wary of incurring Beijing's wrath and losing lucrative access to the mainland's huge economy.
Hong Kong is one of many developing conflicts between China and the United States, on top of trade, the South China Sea and the coronavirus pandemic.
"We deplore this decision", European Council head Charles Michel told a press conference Tuesday. "We are disappointed that China can not fulfill its commitments, which also proves that the "one country, two systems" is not feasible".
China said it would take unspecified "countermeasures" in response.