HONG KONG (AFP) - Three people were injured Sunday (Oct 2) after Hong Kong police fired shots to stop a knife attack on a man, in a rare case of violent street crime in one of Asia's safest cities.

Police said those wounded were two assailants and the man being attacked, and that all three were of "South Asian" origin.

"Five to six...men, with some carrying knives, were attacking another man," police officer Ma Wai-hing told reporters at the scene of the incident in the city's commercial district of Yau Ma Tei.

No further details were given about the attack.

"After verbal warnings were ignored, four shots were fired. Two men were shot," he said. The pair were arrested and hospitalised with wounds to the forearm and waist. They, along with the knife attack victim, are in a stable condition, Ma said.

Footage uploaded to the website of Chinese language newspaper Apple Daily showed a uniformed officer pointing a gun at a group of men - some of whom were wielding knives over a man on the ground - before shots were fired. The officer can be heard yelling "put down your weapon" in Cantonese.

Police said four shots were fired as the first shot was "ineffective" in stopping the attack.

An AFP reporter at the scene said a road intersection was cordoned off around noon, with detectives gathering evidence and two fillet knives lying on the ground.