Some protesters threw bricks at police outside the nearby Chinese People’s Liberation Army base in the Admiralty district of the city and tore down and set fire to a red banner proclaiming the 70th anniversary on Oct. 1 of the founding of the People’s Republic of China.

One water cannon caught fire after being hit by a petrol bomb. The water cannon fired blue jets of water, used elsewhere in the world to help identify protesters later.

“Radical protesters are currently occupying Harcourt Road in Admiralty, vandalizing Central Government Offices and repeatedly throwing petrol bombs inside,” police said in a statement.

The Chinese-ruled territory has been rocked by more than three months of clashes, with demonstrators angry about what they see as creeping interference by Beijing in their city’s affairs despite a promise of autonomy.

On July 1, the anniversary of the city’s 1997 return from Britain to China, protesters wearing hard hats, masks and black shirts laid siege to the Legislative Council building and swarmed inside.

Violence has broken out on previous weekends with protesters trashing metro stations and setting fires in the streets. The police have responded with tear gas, rubber bullets and water cannon.

The spark for the protests was planned legislation, now withdrawn, that would have allowed people to be sent to mainland China for trial.