Clashes between protesters and riot police continued well into Tuesday night at a prominent Hong Kong university, extending one of the more violent stretches in the five months of demonstrations.

Police fired rounds of tear gas and rubber bullets at protesters at the Chinese University of Hong Kong, and students responded by throwing bricks and gasoline bombs.

Clashes continued until police eventually used a water cannon truck and then began a retreat.

The weekday clashes — thus far unusual for the Hong Kong protests which have largely occurred on weekends — followed a day of chaos as protesters erected barricades on roads and subway tracks.

Hong Kong Chief Executive Carrie Lam called the protesters who threw Tuesday's rush hour commute into chaos "extremely selfish."

Dozens of passengers aboard a commuter rail line were forced to exit the train when it stopped short of the station.

Thousands of protesters staged a "flash mob" demonstration in the city's central business district at midday, chanting "five demands, not one less, a reference to their demands for democracy, an independent probe into allegations of police brutality and other issues.

Tensions have escalated in Hong Kong after a policeman shot a 21-year-old protester Monday as he was physically struggling with another protester he was attempting to arrest. The city's hospital authority says the protester was in critical condition. A man set on fire after he was doused with gasoline in a separate incident is also in critical condition.



Lam denounced the violence Monday, telling protesters it is "wishful thinking" that the Hong Kong government will give into protesters "so-called political demands" in order to quell the violence.

The protests were initially sparked by a proposed extradition bill that would have allowed criminal suspects to be sent to mainland China to face trial, but have since evolved into demands for full democracy for Hong Kong. More than 3,000 people have been arrested since the demonstrations erupted

U.S. State Department spokeswoman Morgan Ortagus issued a statement Monday condemning "violence on all sides" and urged "all parties — police and protesters — to exercise restraint."