Hong Kong police fired tear gas in the heart of the Central financial district and at two university campuses after territory-wide transport disruptions wreaked commuter havoc in the Chinese-ruled city.
A flash mob of more than 1,000 pro-democracy protesters, many wearing office clothes and face masks, rallied in Central for a second day, blocking roads below some of the city's tallest skyscrapers and most expensive real estate.
After they had dispersed, police fired tear gas at a few remaining protesters on old, narrow Pedder Street. Police made more than a dozen arrests.
Police vans surged into the area, and officers took up positions in a standoff with protesters just an hour or so before office workers were due to start leaving for home.
"Let's stop focusing on the result. The result is all this chaos and madness. But what is the root cause? We don't have a fully democratic system," said one demonstrator, a 25-year-old property manager wearing a white shirt, black suit pants and a black face mask who gave his name as Roy.
"We want to enjoy air-conditioning and a beer with friends. No Hong Konger wants this (violence), but the government is forcing us to take things to such a dramatic (level)."
Police on Monday fired volley after volley of tear gas in Central, where some protesters blocked streets lined with banks, top-brand shopping malls and jewellery shops. Most had pulled down their shutters on Tuesday.
Emily, in her 30s and working in the finance sector, was carrying a black leather shoulder bag and wearing a black mask and swimming goggles on the front line on Tuesday.
In the bag was a bowl to cover tear gas canisters when they land on the street and a gas mask.
"I won't take part in the attacks, I am here to try to protect the kids," she told Reuters.
Tension eased as the lunch hour ended, but some protesters used a double-decker airport bus to block a key road running alongside the newly reclaimed area of the harbour close to downtown Central.
Police also fired tear gas at City University in Kowloon Tong, beneath the Lion Rock, and at Chinese University on the other side of the mountain, where protesters threw petrol bombs and bricks at police.
Streets inside and outside the Chinese University campus entrance were littered with bricks, other debris and small street fires as police tackled some protesters to the ground. A van used as part of a street barricade was set ablaze.
The university said some people had broken into a storeroom and taken bows, arrows and javelins. All were later retrieved, it said.
There was chaos earlier as people thronged metro stations only to stream out again after some train services were suspended.
Some roads were closed with long traffic jams building during rush hour, a day after some of the worst violence to rock the former British colony in decades. A protester was shot by police and a man set on fire on Monday.
Hong Kong leader Carrie Lam said protesters were being extremely selfish and hoped that universities and schools would urge students not to take part in the demonstrations.
More than 260 people were arrested on Monday, police said, bringing the total number to more than 3,000 since the protests escalated in June.
Protesters are angry about what they see as police brutality and meddling by Beijing in the freedoms guaranteed under the "one country, two systems" formula put in place when the territory returned to China in 1997.
China denies interfering and has blamed Western countries, including Britain and the United States, for stirring up trouble.