Dozens of pro-democracy activists broke into Hong Kong’s government compound on Friday night, leading to several arrests.
Week-long student protests have hit out at Beijing’s refusal to allow fully democratic elections in the Chinese territory in 2017.
Voters will instead have to choose the next Chief Executive from a list of pre-approved candidates.
On Friday, protesters forced their way past police barricades but were met by police signs warning them to stop charging. Officers then used pepper spray to disperse them.
Among several people held was student protest leader Joshua Wong. He was dragged kicking, screaming and bleeding by police.
About a thousand people remained outside the compound in the early hours of Saturday.
Organisers plan to step up their campaign, predicting one of the most disruptive protests seen for decades in Hong Kong’s financial hub on Wednesday.