Throughout the afternoon officers were heckled by people shouting slogans such as “Give me back my vote!” and “Corrupt cops!” as officers conducted multiple stop and searches and ordered crowds to disperse.
In a Facebook statement, police said at least 289 people were arrested, mostly for unlawful assembly.
One woman was detained under a new security law Beijing imposed on the city for chanting independence slogans, the force added.
Live images showed three prominent pro-democracy politicians — Leung Kwok-hung, Figo Chan and Raphael Wong — were among those held.
The protests came hours after the police’s newly formed national security unit arrested Tam Tak-chi, another democracy activist and radio DJ, for “uttering seditious words” — a colonial-era offence.