Hong Kong police fired tear gas in tertiary institutions for the first time on Monday, with Chinese University turned into a smoking battlefield where student protesters and officers were locked in a tense stand-off for seven hours.
The widespread traffic disruption in the morning, caused by anti-government protesters calling for a citywide strike, also prompted 11 universities to cancel classes.
All but one of them would continue to suspend classes on Tuesday.
On Monday morning, police entered Chinese University (CUHK), Polytechnic University and the University of Hong Kong (HKU) to take action against protesters, firing tear gas on the first two campuses.
The confrontation at CUHK in Sha Tin started at 8am, after objects were seen thrown onto MTR tracks at a nearby station.
Police then entered the campus through a bridge from an entrance near Tolo Harbour and set up a defensive perimeter there.