Police fired tear gas as a group of demonstrators reportedly split off from the main rally and marched beyond the designated finish line of its route toward the central government secretariat building, the South China Morning Post newspaper said.
As thousands of protesters rallied in Hong Kong, some of them surrounded a local police station and began throwing bricks and eggs at it, the report added.
According to the newspaper, the protesters blocked roads and caused disruption to traffic.
The report comes after Hong Kong police reported on 3 August that rallies severely disrupted traffic in the city, including in the Cross-Harbour Tunnel connecting Hong Kong with mainland China. Shortly after, police said they had to fire tear gas in a bid to curb arson and public unrest near Tsim Sha Tsui Police Station.
Mass rallies erupted in Hong Kong in early June as the authorities were considering adopting a bill that would allow the autonomous Chinese city to extradite suspects to jurisdictions with which it did not have an extradition agreement, including mainland China. Pressured by the protests, the government indefinitely suspended the bill, while Hong Kong Chief Executive Carrie Lam issued a public apology. However, the protesters still demand the complete withdrawal of the extradition amendments.