Pro-democracy students besieged and trapped by police at a Hong Kong university for days have resorted to daring escapes — including crawling through narrow sewer tunnels in search of a way out.

Some demonstrators were spotted lowering themselves into the drainage system at Hong Kong Polytechnic University early Tuesday, wielding flashlights, wearing gas masks and covering their bodies in plastic wrap.

“The people outside can’t help us. So what can we do?” one protester told a local TV station as he prepared to climb down a manhole.

One masked man pulled himself back up about 10 minutes after attempting to flee through the tunnels, telling the South China Morning Post: “It was disgusting inside the drains.”

“We resorted to doing so because we did not know how to seek help from the outside world,” the man said.

One man who did make it through the tunnels to safety told Vice that about 100 of his compatriots had also managed to flee via a narrow passageway — before police discovered the exit and closed it off.

“We found a route through the railway and some underground tunnels to escape from the campus,” said the 22-year-old man, who asked not to be identified.

“It’s not 100 percent safe, but at least some of us made it out that way,” he said.

Others have escaped by sliding down ropes to waiting motorcycles on a highway below.

By late Tuesday, about 800 people, including 300 minors, had surrendered and left the university, which has been surrounded by tear gas-wielding cops in riot gear since Sunday.

Demonstrators have fought back, launching homemade gasoline bombs and firing arrows.

About 1,000 people have been arrested on charges that include rioting and possession of offensive weapons, police said. Some 200 of those injured in the clashes have been treated at hospitals. Only a small group of protesters — estimated at about 100 — remained huddled on campus early Wednesday.

The holdouts said they feared being arrested or shot at by cops with rubber bullets and water cannons. “If we surrender, they will still put us to jail,” one protester, a mechanical engineering student who would only give his name as Matthew, told AFP.

“It seems we have two options, but actually, we only have one … which is jail.”

The siege was the culmination of the most intense anti-government protests the semi-autonomous city has seen since June, when widespread unrest began.

Families of those at the campus feared the situation could escalate and turn deadly if cops stormed inside to make arrests.

“I’m worried when the police go in to attack there will be heavy casualties, a Tiananmen 2.0,” the mother of an 18-year-old protester told AFP.

With wires