Embattled Chief Executive Leung Chun-ying has said his administration was determined to "take all necessary actions to restore social order" and pave the way for government staff to resume work by tomorrow morning.
The protesters are demanding the right to nominate who can run as the international financial hub's next leader in 2017 elections, as China insists only pre-approved candidates like Leung can stand.
Protest group Occupy Central said demonstrators would leave a secondary Mong Kok site on Sunday to reinforce the main rallying point near government offices across the harbour, and would also allow access to a blockaded road near the downtown headquarters in the Admiralty district.
But their announcement was not backed up by defiant student groups, which kicked off the week-long demonstrations earlier than the older activists of Occupy Central had planned.
Scholarism, led by 17-year-old activist Joshua Wong, and the Hong Kong Federation of Students both issued statements saying they had not told supporters to relocate to the main site.
In a minor breakthrough, student leader Lester Shum met Sunday with mid-ranking officials with the aim of setting conditions for a meeting with Leung's deputy Carrie Lam.
University staff made an impassioned plea earlier in the day for students to head home after Leung said the government was determined to clear the streets.
"The most pressing task for the government is to reopen access to the CGO (Central Government Offices) on Monday so that some 3,000 CGO staff can return to their workplace and continue to provide services to the public," he said late Saturday.
Secondary schools in the affected areas would also reopen, the Education Bureau said, as the city administration pushed for Hong Kong to get back to normal.
Leung, who was voted into office by 689 people on a pro-Beijing committee numbering just 1,200 two years ago, issued an ominous warning if the protests are not ended.
"The situation may probably evolve into a state beyond control, and will have serious consequences to public safety and social order," he said.

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