The Hong Kong government should hold its first talks with pro-democracy representatives this week, an official said late on Monday, as student leaders vowed to keep up the protests.

Protesters said they would not withdraw from three sites in the city until discussions had been successfully concluded, even as the number of participants dwindled. They demanded that the government not use force to clear them.

Lau Kong-wah, undersecretary for constitutional affairs, said he had agreed to multiple rounds of discussions conducted on a basis of equality. He believed that the two sides should resolve disagreements over the venue and the issues to be discussed on Tuesday.

But even if the meeting goes ahead there seems to be little prospect of substantial movement. Lau reiterated that the framework set out by Beijing for universal suffrage should be followed if Hong Kong wanted electoral reform, the South China Morning Post reported. Protesters have demanded civic nominations – something Beijing has made it clear it will not tolerate.

Lester Shum of the Hong Kong Students Federation said Lau’s strong stance might make constructive talks difficult, telling reporters: “We want it to be a substantive dialogue, not just a casual chat or a consultative session.”

Alex Chow, another student leader, said earlier: “It’s up to the government now. This is the first step, but the pressure has to continue.”

Schools reopened on Monday morning and government employees returned to work, a few wearing yellow ribbons, a symbol of support for the movement.

Chief executive Leung Chun-ying, who has rejected protesters’ calls for his resignation, gave another televised address on Monday evening saying the government would seek sincere dialogue on political reform, but reiterating his call for people to return home.

Referring to Mong Kok, where peaceful protesters came under violent attack and complained police did too little to protect them, he said: “Many of those gathering in different areas are young people and students who have passion and love for Hong Kong. However, there are also some radical and violent people. The police will resolutely enforce the law against those who resort to violence, no matter what their stance is on the ‘Occupy Central’ movement.”

He did not repeat his previous warning that “all necessary actions” would be used to clear streets.

Hong Kong police said they found 25 knives and 25 pairs of gloves at two sites near Admiralty on Monday, but that no motive had been established and no one had been arrested.

The remaining protesters had defied Leung’s Monday morning deadline to withdraw. A few hundred slept on the tarmac at the main occupation zone at Admiralty, around government offices, but allowed workers to enter the buildings. A much smaller number remained at Mong Kok in Kowloon.

But thousands returned in the evening to listen to speeches and continue the occupation. Social worker Catlyn Ho, 26, came with friends after finishing work to hand out pink and orange gerberas to government employees heading home.

“Many civil servants have had their road to work blocked and feel annoyed. We hoped this would help them to understand us and our aims. We are not trying to give them trouble, but to fight for true democracy,” she said.

Some employees ignored them or rejected the flowers and complained about the inconvenience the protests had caused, but others voiced their support, Ho said.

She added that after over a week of protesting she was planning to go home to sleep.

“It’s getting really tiring because it’s such a long campaign,” she said, adding that she would come back if it appeared force might be used to clear the streets.

Asked if she believed the movement could now win real concessions from the government, she shook her head and replied: “No.”

Many of the protesters do not identify themselves with any of the groups who initiated the movement: the federation, the student group Scholarism and Occupy Central, which originally planned the civil disobedience campaign. That will inevitably make it harder to bring a smooth conclusion to the campaign – but may also make it easier for police to clear them.

At Causeway Bay, where just a few dozen people remained, office worker Anson said: “The police must want to get rid of us, but they used tear gas before and it brought them a lot of problems.”

But he added: “If people see police arresting others, they will just run away.”

He acknowledged: “I think the chance [of civil nomination] is small, but we still need to fight for it. We don’t know the conclusion and until you get to the end so we must try everything. If we just accept this – if we don’t get real universal suffrage – maybe we won’t get it in future.”

Michael Davis, a professor at Hong Kong University, told AP: “They can’t sustain attendance in protests if it goes on and on.

“They need some strategy where they can withdraw the crowds so they can say to the government that if they are not sincere they will mobilize crowds back on the streets.”

Publishing tycoon Jimmy Lai, a keen backer of the protests, told Bloomberg: “When promises are broken, people will come back.”