HONG KONG- Hong Kong riot police armed with shields dispersed a crowd of 300 pro-democracy activists holding a singing protest in an upmarket shopping mall on Sunday, despite a ban on public gatherings of more than four people.

Chanting popular protest slogans, mostly young activists clad in black swarmed the Cityplaza mall shouting "Liberate Hong Kong, revolution of our times!" while others called for the release of pro-democracy activists.

The protest was the first sizable gathering since the government imposed the ban on public meetings at the end of March to curb a spike in coronavirus infections.

Fears that Beijing is flexing its muscles over the Asian financial hub risk reviving anti-government protests after months of calm as social distancing rules start to ease.

Political tensions have escalated over the past two weeks after the arrest of 15 pro-democracy activists in the city's biggest crackdown on the movement. Beijing has said it supported the arrests in the Chinese special administrative region.

On Sunday, police cordoned off sections of the Cityplaza mall, prompting some stores to shut as activists and shoppers, including families with children, were ordered to leave.

"People were just singing, it's very peaceful ... we didn't do anything illegally. Democracy and freedom is more important," said a high school student surnamed Or who came to participate ahead of his university entrance exam on Monday.

Adding to concerns that Beijing is increasingly meddling in the city's affairs - a claim the central government rejects - Beijing's top official in there urged local authorities last week to enact national security legislation as soon as possible.

(Reporting by Jessie Pang and Tyrone Siu; Writing by Farah Master; Editing by David Clarke) ((farah.master@thomsonreuters.com; +852 28431631 ;))