Hong Kong police said on Monday they arrested 36 people, the youngest aged 12, after violence during anti-government demonstrations escalated as protesters hurled Molotov cocktails at security forces who responded with water cannon and tear gas.

Sunday's protests saw some of the fiercest clashes yet between police and demonstrators since violence escalated in mid-June over a now-suspended extradition bill that would have allowed Hong Kong people to be sent to mainland China for trial.

Police fired water cannon and volleys of tear gas in running battles with brick-throwing protesters on Sunday, the second day of violent clashes in the Chinese-ruled city.