Thousands of people are demonstrating in Hong Kong's financial district after protest leaders called for a show of strength.
It comes after the territory's deputy leader called off talks with student leaders scheduled for Friday.
Carrie Lam said the students' refusal to end their protest had made "constructive dialogue" impossible.
The protesters, demanding full democratic elections in 2017, paralysed parts of Hong Kong in recent weeks.
Throughout the week only a few hundred protesters, mostly students, remained on the streets around the financial and government district of Admiralty and in Mong Kok north of the harbour.
But after the talks were cancelled, leaders of the student movement called on supporters to return to the streets.
"Come to occupy the road outside the public headquarters, come bring your tents to show our persistence on long term occupy action," said Joshua Wong, the 17-year-old founder of the Scholarism movement.
A BBC correspondent reports the activists are hoping a new show of strength will be enough to sustain the movement.
"We are now planning on further action for escalating [the campaign] if the government keeps denying the meeting," said Alex Chow, secretary general of the Hong Kong Federation of Students (HKFS).
The protesters want to be able to directly elect Hong Kong's leader, the chief executive, in the 2017 election.
China has said that, under Hong Kong law, voters will be able to vote freely but from a list approved by a nominating committee.
Ms Lam has accused the students of "undermining trust" in the proposed talks by repeatedly calling people out to protest.