HONG KONG (AP) Hong Kong police fired tear gas and high-pressure water hoses against protesters who had massed outside government headquarters Wednesday in opposition to a proposed extradition bill that has become a lightning rod for concerns over greater Chinese control and erosion of civil liberties in the semiautonomous territory.

The afternoon violence marked a major escalation in the semi-autonomous Chinese territorys biggest political crisis in years. It came after protesters earlier in the day forced the delay of a legislative debate over the bill, which would allow criminal suspects in Hong Kong to be sent for trial in mainland China.

The overwhelming young crowd had overflowed onto a major downtown road as they overturned barriers and tussled with police outside the government building. But when some appeared to have breached the police cordon around offices of the government and Legislative Council in the city states Wanchai district, leading to the police response, which also included firing nonlethal projectiles.

Earlier, a curt government statement said the session scheduled to begin at 11 a.m. would be changed to a later time. Officials gave no indication of when that would be and Hong Kong leader Carrie Lam canceled a scheduled news briefing.

The delay appeared to have been at least a temporary victory for the bills opponents, whose protests are the largest since pro-democracy demonstrations closed down parts of the Asian financial center for more than three months in 2014. Some businesses closed for the day, and labor strikes and class boycotts were called.