Riot police were called to the residential area of Kowloon Bay where rival groups confronted each other in a shopping centre.
A local resident told journalists his son, who was not wearing black - the trademark colour of young protesters in the ongoing anti-government protest movement - was arrested for no apparent reason, Efe news reported.
In the suburbs of Tin Shui Wai, near the border with mainland China, hundreds of demonstrators defied a police ban and took to the streets.
Some waved American flags calling for the US to pass the Hong Kong Human Rights and Democracy Act a congressional bill proposed by some US lawmakers.
If passed, Washington would have to annually certify that Hong Kong remains autonomous from mainland China. Any Chinese officials found violating Hongkongers' human rights and freedoms could have their assets in the US frozen and be denied entry to the country.
A standoff ensued between the demonstrators and riot police who were deployed to the scene and warned the protesters they were involved in an "illegal assembly".
More than 100 secondary school students also held a rally at a square in the city's central business district, where they erected the "Lady Liberty Hong Kong" statue.
The Asian financial hub is in the midst of its most severe political crisis in decades. The crisis was sparked four months ago in opposition to a bill on extradition from Hong Kong to mainland China.
The situation shows no signs of abating, although the city's top leader Carrie Lam formally withdrew the bill 10 days ago. The city's police force has now become the leading subject of criticism for its alleged brutality against protesters during these months.
( With inputs from IANS )