Protesters had gathered cardboard boxes, rubbish bins, and other debris before setting fire to them.
Firefighters quickly arrived to douse the flames.
Large groups of riot police then arrived, scattering the protesters, who calmly walked away right before the officers got there.
The MTR corporation then announced that services to both Prince Edward and Mong Kok stations would be suspended for the time being.
When police eventually withdrew, the crowds returned, placing more debris on Nathan Road to block traffic once again, as well as setting another fire.
Earlier, police shot at least one bean-bag round at protesters after dozens gathered outside the police station to shine laser pointers at officers and throw things at them.
Officers also sprayed what’s thought to be tear gas solution towards protesters after warning them against throwing hard objects towards the station.
A woman was taken away by ambulance after complaining of feeling unwell.
Another woman was seen to be pepper-sprayed after yelling at a group of officers who had briefly emerged to try to disperse the protesters.
However, the black-clad demonstrators refused to leave, and the crowd grew larger as the night wore on.
Last updated: 2019-09-22 HKT 23:35