Governments around the world condemned violence on all sides a day after protesters stormed Hong Kong's Parliament, although some backed the protesters and urged Beijing to uphold the city's freedoms of expression and peaceful assembly.
US President Donald Trump, who said he and Chinese President Xi Jinping talked briefly about Hong Kong when they were in Osaka for the Group of 20 Summit, said the protesters were after democracy.
"They are looking for democracy. And I think most people want democracy. Unfortunately, some governments don't want democracy," he said, calling the protests "very sad".
A US State Department spokesman urged all sides to refrain from violence, adding that Hong Kong's success was predicated on its rule of law and respect for fundamental freedoms, including freedoms of expression and peaceful assembly.
Others in Washington were more critical of what they saw as Beijing's encroachment on Hong Kong's promised autonomy.
House Speaker Nancy Pelosi said: "For weeks, the people of Hong Kong have inspired the world as they stand up in protest against the reprehensible extradition Bill. Neither the G-20 nor the world should ignore their courage as we mark 22 years since the start of China's so-called 'one country, two systems'."
British Foreign Secretary Jeremy Hunt stressed that Britain's support for Hong Kong and its freedoms was "unwavering", while warning there would be serious consequences if Beijing did not honour the 1984 Sino-British treaty which set out the terms for Britain's handover of the city to China in 1997.
"We in the UK condemn violence on all sides, and many people who strongly support the pro-democracy demonstrators in Hong Kong will have been deeply dismayed by the scenes they saw on TV last night," Mr Hunt told the BBC.
"But we urge the authorities not to use what happened as a pretext for repression, but rather to understand the root causes of what happened, which is a deep-seated concern by people in Hong Kong that their basic freedoms are under attack."
The comments from the US and Britain drew sharp rebukes from China, which opposed the "gross interference" and said no country had a right to interfere in its internal affairs.
In Taiwan, many saw parallels between the protests and the "Sunflower Movement" in 2014, when young Taiwanese activists opposed to a trade pact with China occupied Parliament.
"I worry that there might be a worse confrontation ahead if people's demands remain unaddressed," the Central News Agency quoted Taiwanese President Tsai Ing-wen as saying.
Japan was watching the situation with great concern, chief government spokesman Yoshihide Suga said. He noted that Prime Minister Shinzo Abe had pointed out to Mr Xi, when they met last week, the importance of a free and open Hong Kong to the city's prosperity.
• Additional reporting by Walter Sim