HONG KONG - Hong Kong police confirmed that officers fired three live rounds in Tsim Sha Tsui at around 3am on Monday (Nov 18), hours after issuing a warning that officers would retaliate with live bullets if protesters continued attacking them with lethal weapons, local media reported.

The police said a 20-year-old female protester had been arrested and was being escorted to an ambulance, when a "mob of rioters" assaulted officers and helped her escape, broadcaster RTHK reported.

Online video showed a group of black-shirted protesters gathered around a stationary ambulance at the intersection of Jordan Road and Canton Road, with two police officers inside the vehicle.

A close-up video shows black-shirted protesters throwing bricks and bottles.

The police said people had been throwing bricks and splashed an unidentified liquid at the officers. Videos also showed people rocking the ambulance back and forth repeatedly.

The police said one officer, facing grave threat to his life, fired three shots, but initial investigations suggest that no one was hit, RTHK said.

Most people scattered after the first two shots were fired, but video footage showed that some protesters then lobbed Molotov cocktails at the ambulance, striking the vehicle, before a third gunshot was heard.

In a statement on Monday, the police warned people whom they described as rioters to stop using lethal weapons to attack officers and to halt other acts of violence, saying officers would respond with force and possibly live bullets if necessary.

Demonstrators, angry at what they see as Chinese meddling in the former British colony that has had autonomous status since returning to Chinese rule in 1997, have said they are responding to excessive use of force by the police.