Hong Kong riot police have clashed with protesters who defied warnings not to march in an area where demonstrators were targeted by a mob of masked men last week.
Officers fired tear gas cannisters into a crowd of demonstrators in the town of Yuen Long today, as both sides were locked in a standoff.
Ugly scenes saw protesters launching missiles including plastic stools, umbrellas and water bottles at officers.
Police have said they would be clearing from west to east and told marchers to leave via the subway, CNN reported.
But defiant crowds are using barricades to try and block the progress of police and umbrellas and makeshift wooden shields to form a defensive line.
Protests were sparked last month over an extradition bill that would have allowed suspects to face trial in mainland China, where critics say their rights would be compromised.
Protesters were beaten in Yuen Long by a gang of white-clad assailants last Sunday, as they headed home from the latest mass protest in the summer-long pro-democracy movement.
Police said some of the attackers at the train station were connected to triad gangs and others were villagers who live in the area.
Many protesters carried umbrellas as the march began today which are a symbol going back to the Occupy Central protests that shook Hong Kong in 2014.
The umbrellas also help protesters conceal their identities from police cameras as well as shields against tear gas and pepper spray.
The city's public transport network announced its trains would not be making their usual stops in Yuen Long.
Several businesses and public facilities were closed ahead of the march.
Service at a nursing centre was temporarily suspended, and sports venues shut down early.
A few hours before the march started, a man was arrested in Yuen Long for injuring someone with a knife, police said.
Hong Kong's extradition bill was eventually suspended, but protesters' demands have grown to include direct elections, the dissolution of the current legislature and an investigation into alleged police brutality in the Chinese territory.
A former British colony, Hong Kong was returned to China in 1997 under the framework of "one country, two systems".
The arrangement promises the city certain democratic freedoms that are not afforded mainland citizens, but some residents say these liberties have been steadily eroded in recent years after the arrests of booksellers and democracy activists.
After last Sunday's march, a group of protesters vandalised Hong Kong's Liaison Office, which represents the mainland government.
They spray-painted the building's surveillance cameras and threw eggs and black ink at the Chinese national emblem, an act that Beijing has vehemently condemned.
In response to the police's objection to Saturday's march in Yuen Long, protesters have cheekily labelled the procession a "shopping trip," as well as a memorial service for former Chinese premier Li Peng, who died on Monday.
Li was a hard-liner best known for announcing martial law during the 1989 Tiananmen Square protests that ended in bloodshed.
