Fewer than 100 protesters remained holed up in a Hong Kong university on Thursday as riot police encircled the campus, with some activists desperately searching for ways to escape while others hid.

Some protesters told Reuters they where holding out not for a showdown with police, but because they were innocent and looking for an escape route.

“I won’t consider surrendering. Surrendering is for people who are guilty. None of us inside are guilty,” Michelle, a 20-year-old student, said on the campus of Polytechnic University on the Kowloon peninsula.

Rubbish has piled up around the campus, with trash and debris from homemade petrol bombs littered across the grounds. Many protesters have abandoned their equipment, including gas masks and umbrellas.

Much of the campus is damaged, with rooms vandalised and windows shattered. Electricity and water are still functioning.

The Asian financial hub has had a brief respite from months of often violent demonstrations, with relative calm across the city for the past two days and nights ahead of District Council elections set for Sunday.

The government said late on Wednesday it was closely monitoring the situation to see whether the elections could be held safely.

The university, in the centre of the bustling Kowloon peninsula, is the last campus still occupied by activists during a week that saw the most intense violence since the anti-government demonstrations escalated more than five months ago.

Demonstrators are angry at what they see as Chinese meddling in freedoms promised to Hong Kong when the British colony returned to Chinese rule in 1997.

Beijing has said it is committed to the “one country, two systems” formula granting Hong Kong autonomy.

The unrest marks the most serious popular challenge to Chinese President Xi Jinping since he came to power in 2012.

Some protesters have surrendered while others were held during escape attempts that included clambering down from a bridge to waiting motorbikes and fleeing through the sewers.

Graffiti sprayed on campus buildings read: “I have nothing to lose. I have no stake in society,” summing up the mood felt by many of the protesters on Thursday morning.

Some looked for breakfast in one of the university canteens, which remained stocked with food, including noodles and tomatoes.

One protester, dressed in black clothes with gloves, elbow and knee pads, had about a dozen colourful lighters strapped to his chest, apparently to light petrol bombs. He told Reuters the hold-outs were discussing what to do next.

In the past two weeks, protesters have torched buildings and infrastructure, including a footbridge, mass transit stations and toll booths at the city’s Cross Harbour Tunnel linking Hong Kong island to the Kowloon peninsula.

The protesters say that they are angry at the way the MTR, Hong Kong’s public rail network, has helped riot police, and that shutting down key infrastructure forces the government to listen to their demands for universal suffrage and an independent inquiry into police violence, among other things.

The Cross Harbour Tunnel remained shut on Thursday because of extensive damage, authorities said.

Some train services remained shut, the city’s metro operator MTR Corp (0066.HK) said, while the rural Yuen Long station in New Territories would shut by 2 p.m., to pre-empt demonstrations marking four months since suspected triad gang members attacked protesters and commuters there.

China has accused the United States and Britain of stirring up trouble in Hong Kong and it has criticised the US House of Representatives over its passing of two bills aimed at supporting the protesters and sending a warning to China about human rights.

China’s state Xinhua news agency said a top Chinese official in Hong Kong, Xie Feng, had summoned the US consul-general to denounce the legislation as gross interference and violation of international law.

The anger over the US legislation, which has been sent to the White House for President Donald Trump to sign or veto, comes as the two countries are locked in delicate trade talks.