Thousands of pro-democracy demonstrators surrounding Hong Kong government headquarters braced for a showdown with police on Sunday after accelerating a plan to shut down the heart of the global financial hub.
Leaders and supporters of the Occupy Central with Love and Peace movement urged the public to join the protest to pressure Beijing into scrapping a decision to rule out full elections in the former British colony.
Publishing tycoon Jimmy Lai, a key backer of the democratic movement seen wearing a plastic cape and workman's goggles to fend off further pepper spray attacks, said he wanted as big a crowd as possible, after a week of student demonstrations, to thwart any crackdown on a protest branded as illegal.
"The more Hong Kong citizens come, the more unlikely the police can clear up the place," Lai told Reuters as some activists left the scene to rest.
"I believe more Hong Kong citizens will show up later on Sunday."
Others sat tight, also equipped with make-shift masks, upturned umbrellas and goggles, ready in the case of renewed pepper spray attacks in any police attempt to clear the area.
Some family groups were seen among the crowd, with children wearing swimming goggles and raincoats, while one man in his 90s said he been fighting for democracy since the 1960s.
Veteran democracy campaigner Martin Lee, sporting goggles and white plastic parka, said Hong Kong people believed democracy was good for the city and the rest of China.
"They are prepared to sacrifice the comfort of freedom for the sake of themselves, their children and their children's children," he said.
Hong Kong returned to Chinese rule in 1997 under a formula known as "one country, two systems" that guaranteed a high degree of autonomy and freedoms not enjoyed in mainland China. Universal suffrage was set as an eventual goal.
But Beijing last month rejected demands for people to freely choose the city's next leader, prompting threats from activists to shut down Central. China wants to limit elections to a handful of candidates loyal to Beijing.
Communist Party leaders in Beijing are terrified of calls for democracy spreading to cities on the mainland, threatening their grip on power. Dissent as seen in Hong Kong would never be allowed on the mainland, where student protests calling for democracy were crushed with heavy loss of life on and around Beijing's Tiananmen Square on June 4, 1989.
Organisers said as many as 80,000 people thronged the streets surrounding government headquarters in Admiralty district, galvanised by the arrests of student activists on Friday.
No independent estimate of the crowd numbers was available but the action is being seen as the most tenacious civil disobedience action since 1997.
A week of protests escalated into violence when student-led demonstrators broke through a cordon late on Friday and scaled a fence to invade the city's main government compound after a week of peaceful action. Police used pepper spray to disperse the crowd.
The clashes were the most heated in a series of anti-Beijing protests that underscore the central government's challenge to stamp its will on Hong Kong.
Police have so far arrested more than 60 people, including Joshua Wong, the 17-year-old leader of student group Scholarism, who was dragged away after he called on the protesters to charge the government premises. He was still in detention on Sunday, along with fellow student leaders Alex Chow and Lester Shum.
His parents said in a statement the decision to detain him was an act of "political persecution".
As the crowd built in support of the students, the leaders of Occupy announced they had brought forward their own campaign, which had been due to start mid-week targeting the Central financial district.
The decision sparked anger among some students that their efforts had been hijacked by Occupy, but leaders of both movements later stressed the importance of unity.
Crowd numbers thinned significantly before dawn, sparking appeals from both students and Occupy leaders to maintain momentum.
Occupy organisers said that if they were pushed out of the Admiralty area, they might still try to launch action in Central later.
Along with Hong Kong and Chinese officials, some of Hong Kong's most powerful tycoons and pro-establishment figures have spoken out against the Occupy movement, warning it could threaten the city's business and economic stability.
Police have been training for months in mass-arrest and anti-riot tactics and have cleared special holding areas to deal with large numbers of detainees.