Police in Hong Kong drew their guns on Sunday after a small group of protesters attacked officers with sticks and rods, they also brought out water cannon trucks for the first time.
The confrontations were the latest violence in a summer of protests that have shaken the city’s government and residents.
The main showdown on Sunday evening took place in the outlying Tsuen Wan district following a protest march that ended in a nearby park.
While a large crowd rallied in the park, a group of hard-line protesters took over a main street, strewing bamboo poles on the pavement and lining up orange and white traffic barriers and cones to obstruct police.
After hoisting warning flags, police used tear gas to try to disperse the crowd.
Protesters responded by throwing bricks and petrol bombs toward the police and eventually decided to abandon their position.
Two water cannon trucks and a large group of police vehicles with flashing lights joined riot police on foot as they advanced up the street and met little resistance.
Television footage showed a water cannon being fired once, but perhaps more as a test, as it did not appear to reach the retreating protesters.
Some protesters said they were resorting to violence because the government had not responded to their peaceful demonstrations.
“The escalation you’re seeing now is just a product of our government’s indifference toward the people of Hong Kong,” Rory Wong, who was at the clash after the march, said.
One resident, Dong Wong, complained about the tear gas.
“I live on the 15th floor and I can even smell it at home,” he said.
“I have four dogs, sneezing, sneezing all day … The protesters didn’t do anything, they just blocked the road to protect themselves.”
Officers pulled their guns after protesters chased them down a street with sticks and rods, calling them “gangsters”.
Public broadcaster RTHK said one of its reporters saw a uniformed officer fire a shot into the sky.
Earlier on Sunday, tens of thousands of umbrella-carrying protesters had marched in the rain.
Many filled Tsuen Wan Park, the endpoint of the rally, chanting, “Fight for freedom, stand with Hong Kong”, the South China Morning Post newspaper reported.
Protesters have taken to the semiautonomous Chinese territory’s streets for more than two months.
Their demands include democratic elections and an investigation into police use of force to quell the protests.
A large group clashed with police on Saturday after a march in the Kowloon Bay neighbourhood, building barricades and setting fires in the streets. Police said they arrested 29 people for various offences, including unlawful assembly, possession of offensive weapons and assaulting police officers.
The clashes, while not as prolonged or violent as some earlier ones, ended a brief lull in the violence.
The protests, which began in early June, had become largely peaceful the previous weekend, after weeks of escalating violence.