Video report by ITV News Senior International Correspondent John Irvine
China has issued repeated warnings to protesters, as both sides refuse to back down from their stances on a proposed extradition bill.
Despite the advice, protesters remained defiant, ripping down a Chinese flag and throwing it into the harbour - a small but significant move which will no doubt annoy leaders in mainland China. The move has been condemned by Hong Kong's leadership.
Tear gas used to quell protests
Tear gas was used by authorities as demonstrations in Mong Kok turned violent later in the evening. Protesters sheltered for cover under umbrellas and were pictured running away from the scene.
A police station was reportedly vandalised by protesters, with bricks thrown at the building and spray paint used to emblazon slogans on its external walls.
Nathan Road, which is the territory's shopping equivalent of London's Oxford Street, was mostly shuttered on Saturday evening amid the skirmishes.
Defiant protesters remain adamant that demonstrating is the right course of action.
One woman, who protected her face with a medical mask and protective glasses, told ITV News: "I live in Hong Kong, this is my home.
"I want to protect it. I'm not sure if my sister is going to have kids and I want them to have a long life to live."
She broke down in tears as she made her emotional plea to the country's leaders and the overarching Chinese government to preserve the way of life in Hong Kong.
Protesters tear down Chinese flag and throw it in the harbour
Earlier in the day, protesters downed the Chinese flag, which was hoisted from a flagpole alongside Victoria Harbour. It was then thrown into the water.
The move may be small, but will send ripples to the Chinese leadership which has repeatedly warned protesters actions of dissent will not be tolerated.
Whilst the protests were lawful, those marching were warned to stick to designated routes.
The uprisings are a world away from what the world would normally expect from Hong Kong. The territory has long been held up as a model of stability, this latest spout of a protests moves it further away from that reputation.
Local leaders said protesters: "deliberately destroyed the national flag and violated the National Flag and National Emblem Ordinance."
It added: "The government strongly condemns the radical protesters, deliberately undermines social peace and even challenges national sovereignty."
Why are people in Hong Kong taking to the streets?
The demonstrations started with protesters demanding a bill which would mean extraditions to mainland China were possible was withdrawn.
Since the initial protests, the scope has widened, calling for the broadening democracy and for the territory's chief executive to stand down.
China's poor human rights record and lack of a proper legal system means a proposed extradition bill could be a back door for Beijing to target its opponents in the territory, protesters fear.
The bill is seen as the tightening of Beijing's control over Hong Kong well before planned handover period between British rule to Chinese rule ends.
Demonstrations led the government to delay a proposed debate on the legislation.