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 harbor to Kowloon and beyond to the New Territories in the most widespread unrest in nearly four months.

The South China Morning Post and television reports said 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 not immediate verification of its authenticity.

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

Police fired water cannon and volley after volley of tear gas 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 at a time when the central government is already grappling with a U.S.-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 tear gas 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.