Police attacked a Hong Kong university campus held by pro-democracy protesters early Monday, Nov. 18, [local time] after an all-night siege that included firing repeated barrages of tear gas and water cannons.

Pro-democracy protesters barricaded themselves inside Hong Kong Polytechnic University for days. Police surrounded the area Sunday night and began moving in. The crowd wore raincoats and carried umbrellas to shield themselves.

Riot officers broke in before dawn as fires raged inside and outside the school, but at daybreak, protesters remained in control of most of the campus. Fiery explosions could be seen as protesters responded with catapult-launched gasoline bombs.

Police in riot gear prepare to fire as they move onto the campus of Hong Kong Polytechnic University in Hong Kong, early on Nov. 18, 2019. Hong Kong police stormed onto a university campus held by protesters after an all-night standoff. (Vincent Yu/AP Photo)

The protests were sparked by proposed legislation that would have allowed the extradition of criminal suspects to the mainland. Activists saw it as an erosion of Hong Kong’s autonomy under the “one country, two systems” formula implemented in 1997, when Britain returned the territory to China.

The bill has been withdrawn, but the protests have expanded into a wider resistance movement against the growing control of Hong Kong by Chinese Communist Party, along with calls for full democracy for the territory.

Several hundred people formed a human chain Sunday in central Hong Kong in a peaceful rally in support of the movement. Azaze Chung, a university student, said the government should respond to the protesters’ demands, not just use force against them.

Police in riot gear move onto the campus of Hong Kong Polytechnic University in Hong Kong, early on Nov. 18, 2019. Hong Kong police stormed onto a university campus held by protesters after an all-night standoff. (Vincent Yu/AP Photo)

The protesters held their ground for most of Sunday, as water cannon trucks drove over bricks and nails strewn by protesters to spray them at close range—some with water dyed blue to help police identify protesters afterward.

Protesters began retreating into the university near sunset, fearing they would be trapped as police approached from many directions. The protesters barricaded the entrances to the campus and set up narrow access control points.

Around 21,411 students, alumni, and staff from PolyU have signed a joint statement appealing to the police to stop the use of force around the campus and allow all who were inside to leave safely.

The New York Times reported Sunday that police Superintendent Louis Lau said that live rounds could be utilized as a “necessary minimum force” against protesters.

According to InMedia, police arrested a reporter from the online outlet the Barry Evening Post as he was trying to leave. Multiple student reporters were also arrested, including at least one from City University and Hang Seng University respectively.

Police representatives told the Hong Kong Journalists Association (HKJA) that only reporters who can show press credentials will be allowed to leave. Otherwise, everyone leaving the university will be arrested on suspicion of taking part in a riot.

As the night wore on, former UK Foreign Secretary Sir Malcolm Rifkind urged leader Carrie Lam to exercise restraint: “Hong Kong’s chief executive has the responsibility to do everything possible to prevent a massacre. She must order the police to exercise restraint and not to use live ammunition or other forms of lethal force. A bloodbath on a Hong Kong campus would be devastating for Hong Kong as a whole. I also urge those students who have engaged in violence to stop. I condemn violence on all sides and I call on both sides to show restraint and pull back from the brink,” according to Hong Kong Free Press.

U.S. Rep. Jim McGovern (D-Mass.) on Nov. 17 called on the Chinese and Hong Kong authorities to “immediately deescalate the situation and exercise restraint” at the university.

“More violence [and] bloodshed will only make things worse,” he said in a tweet.

Includes reporting from the Associated Press