Cheung Tze-keung and four of his accomplices were taken away and shot an hour after losing an appeal in the southern city of Guangzhou.

Cheung, who got his nickname from the lavish way in which he rewarded his fellow gangsters, was convicted of a series of a high-profile crimes, including kidnapping, armed robbery, and smuggling explosives.

Although no details were given about the executions, capital punishment in China is usually carried out by a single shot to the back of the head.

Two other gang members received death sentences suspended for two years, and another 29 were given life imprisonment.

Outcry over sentence

Human rights activists argued that mainland China has no jurisdiction over crimes committed in Hong Kong, where there is no death penalty.

The trial, which was held behind closed doors, was the first high-profile cross-border trial since Hong Kong was handed back to Chinese rule last year.

Amnesty International attacked the ruling, saying insufficient evidence was presented. Human rights groups also criticised the Hong Kong Government's refusal to seek extradition.

But Hong Kong chief executive Tung Chee-hwa agreed with prosecutors who said the trial should take place in mainland China as that was where the crimes were planned.