A deepening sense of impasse gripped Hong Kong as pro-democracy protests entered their fourth week, with the government having limited options to end the crisis and demonstrators increasingly willing to confront police.
Dozens of people were reportedly injured in two nights of clashes that began late on Friday in the densely populated Mong Kok district of the Chinese-controlled city, including 22 police. Four people were arrested early on Sunday, police said.
The area was calm early on Monday, although scores of protesters remained on the streets.
Hopes of easing the worst political crisis in Hong Kong since Britain handed the free-wheeling city back to China in 1997 rest on talks scheduled for Tuesday between the government and student protest leaders that will be broadcast live.
But few are expecting any resolution given the two sides are poles apart on how the city will elect its next leader in 2017.
"Unless there is some kind of breakthrough in ... talks on Tuesday, I'm worried we will see the standoff worsen and get violent," said Sonny Lo, a professor at the Hong Kong Institute of Education.
"We could be entering a new and much more problematic stage. I hope the government has worked out some compromises, because things could get very difficult now."
Students want free elections, but China insists on screening candidates first. Hong Kong's Beijing-backed leader, Leung Chun-ying, has said the city's government was unwilling to compromise on China's restrictions, which were announced in late August.
Leung, who has rejected calls by protesters to quit, said on Sunday that more time was needed to broker what he hoped would be a non-violent end to the upheaval.
"To work out a solution, to put an end to this problem, we need time. We need time to talk to the people, particularly young students," he told Hong Kong's ATV Television. "What I want is to see a peaceful and a meaningful end to this problem."
Hong Kong's 28,000-strong police force has been struggling to contain a youth-led movement.
Roughly 1,000 demonstrators in Mong Kok launched a fresh assault early on Sunday, putting on helmets and goggles before surging forward to grab a line of metal barricades hemming them into a section of road.
Scores of riot police had smashed batons at a wall of umbrellas that protesters raised to defend themselves. Amid shouts and hurled insults, scuffles erupted before police surged forward with shields, forcing the crowds back.
On Sunday night, crowds again built up as protesters stockpiled helmets and fashioned homemade forearm shields out of foam pads to parry baton blows. Unlike previous nights, however, there were no clashes.
Besides Mong Kok, about 1,000 protesters remain camped out at the headquarters of the civil disobedience "Occupy" movement on Hong Kong Island in a sea of tents on an eight-lane highway beneath skyscrapers close to government headquarters.
The protesters, led by a restive generation of students, have been demanding China's Communist Party rulers live up to constitutional promises to grant full democracy to the former British trading outpost.
Hong Kong is ruled under a "one country, two systems" formula that allows it wide-ranging autonomy and freedoms and specifies universal suffrage for Hong Kong as an eventual goal. But Beijing is wary about copycat demands for reform on the mainland.
Leung appears hamstrung, unable to compromise because of the message that would send to people on the mainland while more force looks likely to only galvanize the protesters.
"I will continue to stay here until CY (Leung) resigns," said Lap Cheung, 40, who quit his IT job in the United States to return to Hong Kong for the protests, adding that he had no hope for Tuesday's talks.
Hong Kong Security Chief Lai Tung-kwok said some of the clashes in recent days had been initiated by activists affiliated to "radical organisations which have been active in conspiring, planning and charging violent acts".
The city's police chief, Andy Tsang, also expressed frustration on Saturday to say "extremely tolerant" policing had not stopped protests becoming more "radical or violent".
The situation in Hong Kong surfaced in weekend talks between U.S. Secretary of State John Kerry and Chinese State Councillor Yang Jiechi in Boston.
A senior State Department official said Hong Kong was discussed as part of candid exchanges on human rights while a Chinese Foreign Ministry statement said Yang had told Kerry that Hong Kong was purely an internal affair of China.