Hong Kong — Police here fired teargas and rubber bullets at pro-democracy protesters throwing petrol bombs in the Asian financial hub on Tuesday as its Chinese rulers celebrated the 70th anniversary of the founding of the People’s Republic.

Cat-and-mouse clashes spread from the upmarket district of Causeway Bay to the Admiralty area of government offices on Hong Kong island. Violence also escalated across the harbour to Kowloon and beyond to the New Territories in the most widespread unrest in nearly four months.

According to reports in the South China Morning Post and on television at least one person was wounded in the chest by police firing live rounds. Police did not respond to requests for comment but have said they fired live rounds into the air in previous clashes.

Video footage of a police officer firing at a protester at close range went viral, but there was no immediate verification of its authenticity.

Fifteen people were wounded across the territory, one critically, the Hospital Authority said without giving details.

Police fired a water cannon and many volleys of teargas to disperse protesters throwing Molotov cocktails outside central government offices in the Admiralty area and ordered the evacuation of the Legislative Council building next door.

Police said “rioters” had used corrosive fluid in Tuen Mun in the west of the New Territories, “injuring multiple police officers and reporters”. No details were immediately available.

The territory has been tense for weeks, with protests often turning violent, as authorities tried to avoid activists spoiling Beijing’s birthday parade while the central government is already grappling with a US-China trade war and a slowing economy.

By the afternoon, police and protesters were involved in standoffs across Hong Kong, with the streets littered with teargas canisters and other debris.

Nearly four months of street clashes and demonstrations have plunged the former British colony into its biggest political crisis in decades and pose the most serious popular challenge to President Xi Jinping since he came to power.