At around 1 p.m., the demonstrators, many wearing masks in defiance of a new law banning them at public gatherings of more than 50 persons, spilled onto the tramway in Central, chanting slogans such as "Disbanding the police force brooks no delay" and "Fight for freedom, stand with Hong Kong", reports Efe news.
The planned theme of the protest concerned the arrest of several security guards who tried to stop riot police from entering a shopping mall earlier this week, but fresh accusations of police sexually abusing young activists have ratcheted up the anger of protesters.
On Thursday night, during an emotionally-charged public forum with Chinese University of Hong Kong vice chancellor Rocky Tuan on campus, student Sonia Ng wept as she alleged police officers sexually assaulted her - and other detainees - after she was arrested last month.
"Do you know I am not the only one who suffered sexual violence by the police? Other arrestees have suffered sexual assaults and torture by more than one officer, regardless of gender," she said.
She then removed her mask in front of Tuan and more than 1,400 members of the audience and urged the vice chancellor to issue a statement to condemn the police.
It was the first time an alleged victim of sexual misconduct by Hong Kong police officers has revealed their identity since the beginning of the on-going anti-government protest movement, which has so far seen more than 2,300 people arrested.
Several alleged victims, Ng included, have previously spoken of their experiences at press conferences, but they were all heavily masked. The city's police force has denied the allegations.
Around midnight Thursday, the police issued a statement saying it accorded "high priority" to the "serious allegation" made by Ng and asked her to "provide concrete evidence so that we can launch a fair fact-finding investigation as soon as possible."
On Friday morning, Ng told Hong Kong's Commercial Radio that she was considering legal action, and that she has received threats since she spoke out.
On Thursday, Hong Kong's number two official Matthew Cheung revealed that 750 of the 2,379 protesters arrested over the past four months were aged under 18, accounting for about a third of the total, while 104 were under 16.
The chief secretary said the trend was "shocking" and "heartbreaking," adding the authorities "only clamp down on violence" but "never" on legal and peaceful protests.
Hong Kong's youth have been the leading force fronting the protest movement that erupted in early June because of a contentious bill on extradition from Hong Kong to mainland China.
The bill was withdrawn in early September but the movement has morphed into a wider campaign for greater democracy and against alleged police brutality.
( With inputs from IANS )