Hong Kong police shot and wounded one protester who, hospital officials said, was in critical condition on Monday, as the Chinese-ruled territory spiralled into rare working-hours violence in its 24th straight week of pro-democracy unrest.
Police fired tear gas in the Central business district where some protesters, crouching behind umbrellas, blocked streets as office workers on their lunch break crowded the pavements and hurled anti-government abuse.
Some passersby took cover inside the Landmark shopping mall, one of the oldest and most expensive in Central, as volley after volley of tear gas rained down.
Protests have happened almost daily in Hong Kong, sometimes with little or no notice, disrupting business and piling pressure on the government. But it was rare for tear gas to be fired during working hours in Central, lined with bank headquarters and top-brand shops at the foot of Victoria Peak.
The violence usually begins after dusk. Some offices were closing early and workers were heading home.
Police fired live rounds at close range at protesters in Sai Wan Ho on the eastern side of Hong Kong island and said one protester was wounded.
Video footage showed a man lying in a pool of blood with his eyes wide open. Police also threw a woman to the debris-littered street and pepper-sprayed her in the face as plastic crates were thrown at officers.
Protesters built barricades under the hot autumn sun and set fires in the street.
Anson Yip, a 36-year-old Sai Wan Ho resident, said protesters were throwing rubbish to create a road block when police ran to the scene.
"They didn't fight and the police ran and directly shot. There was three sounds, like 'pam, pam, pam'," Yip said.
"They (the protesters) are against the government, that's why the police just shot them."
Police later fired tear gas in the same area. Protesters and residents formed a barricade of polystyrene boxes around the bloodstain beside a pedestrian crossing after police forensic teams left the scene.
"When I arrived the road was blocked and people were yelling at the police, calling them murderers," said a 24-year-old man, one of several office workers gathered there, who gave only his surname, Wing.
Video images circulating online showed a man squirting petrol on another and setting him on fire, apparently outside Ma On Shan Plaza in the New Territories. Though engulfed in flames, the man was able to rip off his shirt and douse the blaze.
Reuters was unable to immediately verify the footage.
Without confirming the video, the Hospital Authority said a man had been admitted with severe burns and was in critical condition.
Police said in a statement radical protesters had set up barricades across the city and warned demonstrators to "stop their illegal acts immediately".
The unrest also spread to Mong Kok, one of the most densely populated areas on earth, on the Kowloon peninsula and often the site of street clashes.
Police did not immediately comment on the shooting. They first began using live rounds as warning shots in August and have shot an 18-year-old protester and a 14-year-old, both of whom survived.
Protesters are angry about what they see as police brutality and meddling by Beijing in the freedoms guaranteed to the former British colony by the "one country, two systems" formula put in place when the territory returned to Chinese rule in 1997.
Some have called for independence, a red line for Communist Party leaders in Beijing.
China denies interfering and has blamed Western countries for stirring up trouble.
The latest violence comes after a student died in hospital last week following a fall as protesters were being dispersed by police.
Violence flared at several university campuses as news of the latest shooting spread, with witnesses reporting tense standoffs between students, protesters and police. All classes were cancelled.
Police fired tear gas at Chinese University, across the river from Ma On Shan in the New Territories, where students hurled petrol bombs and barricaded the campus like a fortress. Students set fire to debris at the Polytechnic University on the Kowloon side of Victoria Harbour.
"I feel a strong sense of helplessness," said one Chinese University student who only gave his name as Chan. "Who wouldn’t want to attend class if they could? The government still isn’t listening to us."
He was guarding a back gate at the university. The old Tai Po Road that snakes uphill from Sha Tin and often featured in 1960s black and white Cantonese movies, was barricaded with fencing, wooden boards, bamboo, poles, bins and other debris.
Services on some train and subway lines were disrupted early on Monday, with traffic snarled and riot police deployed near stations and shopping malls after protesters called for a general strike.
Hong Kong's stock market was down 2.9% in mid-afternoon trade, outpacing losses in other parts of the region.
China has a garrison of up to 12,000 troops in Hong Kong who have kept to barracks throughout the unrest, but it has vowed to crush any attempts at independence.