HONG KONG — Hong Kong police shot a protester with live ammunition Monday morning as tensions soared over a planned general strike that disrupted commuter traffic across the city.

The protester, who appeared to be unarmed, was shot in the stomach by a police officer as he was trying to tackle another demonstrator in a traffic intersection in Sai Wan Ho, video circulating on social media shows.

The 21-year-old male appeared listless, though still breathing, as a riot officer rolled him over from a pool of his own blood. An angry crowd gathered hurling plastic crates at the police before an ambulance arrived and took the injured protester away.

The protester, surnamed Chow, was moved to an intensive care unit after an operation on his ruptured liver and kidney Monday morning, according to medical sources.

The incident highlighted a chaotic morning in the city gripped by five months of relentless protests. What began as single-issue protests over an unwanted extradition bill to China — now withdrawn — has become a widespread and increasingly violent movement against Beijing’s control over the Hong Kong government, seeking accountability for police brutality and demanding democratic reforms.

Early in the morning, demonstrators blocked major arteries and disrupted train service in an attempt to force a citywide strike. Debris was reportedly used to block one rail line and a fire was set in one train car.

Clashes between police, protesters and residents soon broke out across the city after the shooting. At least six universities canceled classes as enraged students set subway stations on fire, threw gasoline bombs and built barricades against police firing tear gas and projectiles on campuses.

In Kwai Fong, a suburban town in the northern New Territories, a police officer chased and rammed into protesters on a motorcycle, zigzagging into them as they ran.

At lunchtime, hundreds of protesters, many in business wear, faced off with police in Hong Kong’s central financial district, calling the police “murderers.”

Pierson reported from Hong Kong and Su from Beijing.