Hong Kong police fired blue dye from a water cannon, rounds of tear gas and a live warning shot as protesters lit fires and threw petrol bombs and bricks on Sunday in clashes ahead of the 70th anniversary of the People's Republic of China.

Despite organizers not requesting permission from authorities, thousands of protesters marched in the 17th consecutive weekend of unrest. Hong Kong's Hospital Authority said 48 people were admitted for treatment, including one person in critical condition.

The latest round of violence came two days before October 1, when Beijing will be hoping to project an image of national strength and unity with a military parade through the city to mark 70 years since the founding of the People's Republic of China. Hong Kong leader Carrie Lam travels to Beijing on Monday to take part in the celebrations.

Although Sunday's Causeway Bay march drew thousands of peaceful protesters of all ages, it took an aggressive turn. Police and protesters clashed in the afternoon, with demonstrators throwing bricks and petrol bombs, blocking roads and setting fires at multiple locations on Hong Kong Island.

Police fired tear gas, pepper spray, rubber bullets and bean bag rounds. Officers also used a water cannon equipped with blue dye — aimed at staining protesters to make them easier to identify later — to clear people from around the Hong Kong government headquarters, an area that has often been a target during the demonstrations.

An officer also fired one warning shot into the air on Sunday evening. “Some police officers were surrounded and attacked by a large group of violent protesters,” police said in a statement. “With their lives under serious threat, an officer fired one warning shot into the sky to protect their own safety.”

It came after protesters gathered on Saturday to mark five years since the start of the pro-democracy Umbrella Movement that brought parts of the city to a standstill for 79 days in 2014. Saturday's demonstrations also featured protesters throwing bricks and petrol bombs at the government buildings, and police using water cannons on the activists.

The protests, initially over a now-withdrawn extradition bill to mainland China, have grown more violent as the weeks have pushed on, with police on Friday announcing that 1,578 people had been arrested in total. The protests have evolved to include five demands, including universal suffrage. Hong Kong presently only has partial democracy, and only 1,200 people vote for the city's leader.

In a statement released on Saturday, a government spokesman said the concept of “one person, one vote” was enshrined in Hong Kong's mini-constitution, the Basic Law, and the government would take steps towards developing it.
When Lam withdrew the controversial extradition bill earlier this month, she said universal suffrage was the “ultimate aim” of the Basic Law.