Protesters crippled Hong Kong for the third straight day on Wednesday as they blocked roads and train services, forcing businesses to close.
Police rained down teargas and rubber bullets on students and protesters, who fought back with molotov cocktails and fiery arrows dipped in petrol.
Hundreds of students have fled after days of violence on several university campuses.
Demonstrators braced for more clashes, some armed with javelins, bows and arrows.
The demonstrators put up barricades and used bricks and projectiles to block roads in several places, including in the central financial district and Mong Kok.
Some protesters gathered at the Cross-Harbour Tunnel tollbooths, setting them on fire and vandalizing them.
Near a subway station, a 70-year-old resident was hit in the head by a brick-shaped object thrown by protesters and is in critical condition according to local media.
As more disruption is expected on Thursday, Hong Kong's subway operator suspended parts of its rail network and the Cross-Harbour tunnel was blocked.
The government ordered the suspension of schools from kindergartens to colleges on Thursday for the first time as clashes turned increasingly violent.
Meanwhile, U.S. Senator Jim Risch said he supports the Hong Kong Human Rights and Democracy Act and said he wants to push forward a bill supporting the protests. This drew an angry response from China on Wednesday.
Chinese Foreign Ministry spokesperson Geng Shuang criticized the senator by saying that "Hong Kong is China's Hong Kong" and no external forces should interfere China's internal affairs.
Eum Ji-young Arirang News.