At least 29 people have been injured since Friday night as Hong Kong police arrested students during a night of scuffles.
Hong Kong riot police fired pepper spray to disperse a crowd on Saturday, after more than 1,000 students joined demonstrations opposing Bejing's decision to rule out fully democratic elections for the Hong Kong's leader in 2017.
"I want to tell CY Leung [chief executive of Hong Kong] and Xi Jinping [general secretary of the Communist Party of China] that the mission of fighting for universal suffrage does not rest upon the young people, it is everyone's responsibility," shouted Joshua Wong, a 17-year-old student leader, as police dragged him away, according to a Reuters report.
Wong is a veteran of organising protests. Most recently, he was involved in a demonstration forcing the Hong Kong government to back down from introducing a Chinese national education curriculum, that some feared was a form of brainwashing.
On Saturday night, around 150 protestors broke their way into a government compound, some scaling a tall fence, stated an AP report.
Protesters linked arms, with some students shouting "civil disobedience" and demanding "free the people", as police surrounded them with metal barricades, .
At least four people were carried off on stretchers with slight injuries. The scene marked the biggest escalation in street protests the city has seen this week.
An Al Jazeera journalist, reporting from the complex, said that some protesters were still inside the compound on Saturday morning, while thousands remain outside.
The standoff continues and the situation is described as "very fluid".
Hong Kong's secretary for security, Lai Tung-kwok, told reporters police acted appropriately and gave students sufficient warning before starting the process of clearing the square.
The scuffles marked the flashpoint in the week-long strike by students demanding China's Communist leaders organise democratic elections in 2017.
Thousands of university and college students spent the week boycotting classes. On Friday they were joined by a smaller group of high school students.
"Our movement is peaceful and does not use aggression," Yvonne Leung, the University of Hong Kong Students' Union president told AP. "Students who decided to storm inside [the government complex] knew about their legal responsibility."