HONG KONG, China (AFP) — Police fired tear gas and water cannons at thousands of Hong Kong pro-democracy protesters who gathered yesterday against a controversial security law proposed by China, in the most intense clash for months.

The planned legislation — expected to ban treason, subversion, and sedition — comes after Hong Kong was shaken last year by months of massive, often-violent protests, and repeated warnings from Beijing that it would not tolerate dissent.

With campaigners warning the proposal could spell the end of the city's treasured freedoms, thousands gathered and chanted slogans in the busy Causeway Bay and Wan Chai districts, while some masked protesters set up makeshift barricades to stop police vehicles.

Riot police were deployed after protesters ignored earlier warnings from authorities against unauthorised assembly, and violated the city's current novel coronavirus-linked law, banning public gatherings of more than eight people.

Despite the alarm in Hong Kong and in some Western capitals, Chinese and city officials have insisted the proposed law is needed to prevent unrest and protect national security.