Hong Kong (CNN) 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.

More than 150 people were arrested over the weekend, police said in a news conference Monday. On Friday, police announced that a total of 1,578 people had been arrested over the course of the protests.

Hong Kong police fire a water cannon toward protesters gathered outside the central government offices after taking part in an unsanctioned march through Hong Kong on September 29.

Protesters threw as many as 100 petrol bombs over the weekend, Police Public Relations Branch chief superintendent Tse Chun-Chung told reporters. In Hong Kong, arson carries a maximum sentence of life in prison

"With the increasing intensity and (extent) of violence over the past three months, there are apparent signs that hardcore violence will escalate in the near future," Tse said, adding that he was concerned about public safety during the upcoming National Day celebrations. "All acts are one step closer to terrorism."

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