Hong Kong police on Thursday banned a planned protest against suspected triad gangs who beat up pro-democracy demonstrators, ratcheting up tensions ahead of what is expected to be another weekend of anti-government rallies.
Protest organisers have vowed to go ahead with their march despite the police denying their request.
Public anger has been raging since last Sunday when a gang of men in white t-shirts, armed with poles and batons, set upon anti-government protesters in a station and on a train, sending at least 45 people to hospital.
Police have been heavily criticised for being too slow to respond to the violence, fueling accusations of collusion or turning a blind eye to the pro-government mob -- allegations the force have denied.
Activists had planned to hold a protest on Saturday in the rural town of Yuen Long where the brazen assaults took place.
But in a rare move, Hong Kong police issued a letter of objection saying they feared reprisal attacks against villagers from protesters.
"Anyone who comes out to march, they would be violating the law," acting regional police commander Tsang Ching-fo told reporters.
Protest organisers vowed to push ahead, raising the likelihood of fresh clashes between demonstrators and police.
"I personally will march," said activist Max Chung, who had applied for police permission, adding he was seeking legal advice.
Social messaging channels used to organise the largely leaderless movement quickly filled up with vows from people to join in.
Some suggested holding a "shopping spree" in Yuen Long. Others suggested, sarcastically, it could be a location to mourn the death on Wednesday of notorious Chinese communist hardliner Li Peng, noting that religious gatherings do not need police permission.
After the police announcement, an AFP reporter saw around a dozen young people in a military supplies surplus store buying protective clothing and vowing to attend.
"We will go regardless," one young man said.
The South China Morning Post said the last time police rejected a protest request was in 2014.
- Graves vandalised -
Yuen Long is in the New Territories, the rural region bordering China where many villagers are staunchly pro-Beijing.
Three days ago the Yuen Long grave of the parents of Junius Ho was vandalised. An ardent pro-Beijing lawmaker, Ho was seen shaking hands with the white-shirted men before Sunday's attack. He also threatened a pro-democracy lawmaker in an online video earlier this week.
The region also has a long reputation for hosting triads. Police on Thursday said 12 people have so far been arrested for Sunday's violence, nine of who have known triad links.
Hong Kong has been plunged into its worst crisis in recent history after millions of demonstrators took to the streets -- and sporadic violent confrontations between police and pockets of hardcore protesters.
The demonstrations were triggered by a controversial bill which would have allowed extraditions to mainland China but have evolved into a call for wider democratic reforms.
On top of Saturday's rally, activists are planning to protest inside Hong Kong's airport arrival gates on Friday and hold a series of marches on Sunday.
The international finance hub has experienced seven weekends in a row of largely peaceful mass rallies followed by violent clashes, an unprecedented challenge to Beijing's authority since its 1997 handover.
Beijing has labelled the protests as "extreme illegal violence", but has left it to the city's semi-autonomous government to deal with the situation.
City leader Carrie Lam has shown no sign of backing down beyond agreeing to suspend the extradition bill.
On Wednesday China issued a stark reminder that its army could be deployed in Hong Kong if city authorities requested support in maintaining "public order", something local authorities have said they have no intention of doing.