Sources said the force had deployed over a thousand officers on the second protest anniversary, with officers stepping up patrol in different districts.
Police forces are standing by at Times Square starting in the afternoon as netizens called on a rally in Causeway Bay and Mong Kok at night.
A large group of officers from the police tactical unit gathered and cordoned off the East Point Road pedestrian precinct at around 3 pm.
Police vehicles are parked at Yee Wo Street. Some people who dressed in black t-shirts were stopped and searched.
The force also had stepped up patrol at the junction of Nathan Road and Argyle Street, Soy Street in Mong Kok, as well as outside of the government headquarter and Legislative Council in Admiralty.
Roadblocks were set up at the Kowloon entrances of the Cross Harbour Tunnel and Western Harbour Crossing.
Police said at around 4 pm, several men dressed in black blocked the road with trash cans near Dundas Street.
The force urged people not to participate in any unauthorized assembly, which might risk violating the law and social distancing measures.