Violence has once again broken out in Hong Kong after thousands of anti-government demonstrators attempted to march through the city, in defiance of a ban.

Protesters had gathered in the centre of the city for the demonstration which was approved by authorities - as long as participants stayed in one location. But the protest moved, in defiance of the ban on marching and of a prior police warning that they would stop anyone attempting to march.

Riot police fired tear gas at protesters and arrested several people.

Al Jazeera's Sarah Clarke joins us live from Hong Kong.