A weeklong police siege of a university in Hong Kong may be winding down, closing one of the more violent chapters in the city's long-running anti-government protests.

A search of the Hong Kong Polytechnic campus on Tuesday found just one woman, in weak condition, and a senior university official said it's unlikely anyone else remains.

A few people might still be hiding in the warren of buildings on the urban campus, trying to avoid arrest. The search apparently didn't find a man who told reporters before dawn that he is happy living at the university and 'everyone can stop worrying about us.'

Police have cordoned off the area to try to prevent anyone from escaping.

Polytechnic University vice-president Alexander Wai, who led a search of the campus by seven teams, said he couldn't rule out that some people have remained, but 'the possibility is not very high.'

Attention in Hong Kong has shifted to city leader Carrie Lam's response to a major loss in local elections on Sunday. The results were seen as a public rebuke of her tough line on the protests.

Lam, after issuing only a written statement on Monday, offered no concessions to anti-government protesters, saying only that she would accelerate dialogue and identify ways to address societal grievances.

She said the central government in Beijing did not blame her for the election setback, and that while it may have reflected unhappiness with the government's handling of the unrest, it also showed that many people want an end to the violence.

'Let me just stress that after these five-six months, Hong Kong people have realised very clearly that Hong Kong could no longer tolerate this chaotic situation,' Lam told reporters after a weekly meeting with advisers. 'Please help us to maintain the relative calm and peace that we have seen in the last week or so and provide a good basis for Hong Kong to move forward.'

Her refusal to compromise could spark more unrest at a time when the semi-autonomous Chinese territory has plunged into its first recession in a decade.

The streets around Polytechnic were the scenes of fierce clashes with police 10 days ago. Protesters used the campus as a base and shut down access to a major roadway under Hong Kong's harbour, setting the toll booths on fire.

The Cross-Harbour Tunnel will reopen on Wednesday morning, earlier than expected, a senior city official announced.

The seven search teams went through most of the buildings on the Polytechnic campus, finding one woman who appeared physically weak, a university statement said.

Wai, the vice-president, said she is over 18 and not a student of the university. A Red Cross first aid team gave her medical care, and counselors were trying to coax her to surrender.

Holdouts at the university had been trying to avoid arrest.

The search teams found gasoline bombs and other dangerous items, the Polytechnic said in a statement. The library was flooded, and the fuel tanks of cars had been forced open.

The university plans to resume the search in the morning, possibly with more people.

The pro-democracy bloc won control of 17 out of 18 district councils in Sunday's election, which was seen as a barometer of public support for more than five months of pro-democracy protests.

Lam said that when she withdrew an extradition bill in September that had sparked the protests, she also gave a detailed response to the protesters' other demands, including free elections for the city's leader and legislature and a probe into accusations of police brutality.

The government hopes to take advantage of the current lull in violence to accelerate public dialogue and set up an independent review committee to find solutions to deep-seated societal issues, she said.

'The next step to go forward is really, as you have put it, to engage the people. And we have started a public dialogue with the community,' Lam said. 'But unfortunately, with the unstable environment and a chaotic situation, I could not do more on that sort of engagement. I hope that the environment will allow me to do it now.'

Some pro-establishment figures have pointed fingers at Lam for their loss, while the pro-democracy camp has asked her to step down.

Protesters saw the extradition bill as an erosion of their rights promised when the former British colony returned to Chinese control in 1997. The demonstrations have since expanded into a protest over what they see as Beijing's growing interference in the city.

Some analysts said China's ruling Communist Party isn't likely to soften its stand on Hong Kong. Chinese media have muted reports on the poll outcome, focusing instead on how pro-Beijing candidates were harassed and the need to restore law and order.

Beijing is treading cautiously partly to avoid jeopardising trade talks with the United States. It also faces pressure from planned US legislation that could derail Hong Kong's special trade status and sanction Hong Kong and China officials found to violate human rights.

China's foreign ministry on Monday summoned US ambassador Terry Branstad for a second time to demand Washington block the bipartisan legislation on Hong Kong. Vice-minister Zheng Zeguang warned that the US would 'bear all the consequences that arise' if the bill is signed by President Donald Trump.

Trump has not committed to signing it and has 10 days from the time of its passage last week to veto it. If he does not do so, it automatically becomes law. Congress could also override a veto with a two-thirds majority vote in both houses.

Derek Mitchell, a former US ambassador to Myanmar who heads the Washington-based National Democratic Institute, denied accusations that it had funded or supported the Hong Kong protesters. China has accused foreign forces and money of being a 'black hand' behind the protests.

Mitchell, speaking in Hong Kong, said citizens had spoken 'loudly and clearly' in the local election and that the government must respond to prevent the protests from sliding into an abyss.

'The ball is in the court of the government here and authorities in Beijing,' he said.

In a boost to the city, Chinese e-commerce giant Alibaba made a strong debut on the Hong Kong stock exchange on Tuesday, rising 6.6%. Alibaba's share sale of at least $11.3 billion in its secondary listing is the world's biggest this year.