Police Maj-General Hanpol Nitwibul, head of the special unit to crack down on gunmen and influential figures, said the suspect was shot after opening fire at police officers, who had asked to search him.

The killing was reported to the Pathumwan police station, which has jurisdiction over the area, at 11.30pm.

Officers from the station initially identified the suspect as Wichai Ritthinetikul, 31, from an ID card found on his body -  on the footpath outside the Royal Bangkok Sports Club.

They said he died of two gunshot wounds to the chest.

A 9mm pistol, plus a bag containing eight kilograms of heroin - worth nearly Bt1 billion - and six spent cartridges, were allegedly found lying nearby.

Hanpol, whose unit is part of a special force under deputy national police chief Police General Preawpan Damapong, said he and about 20 officers had staked out the spot following a tip-off that a drug deal would take place there.

He said the suspect got out of a taxi at 11pm and walked about for five minutes before starting to leave. Police officers then asked the man if they could search him but he pulled a gun and fired at them, forcing them to fire back, Hanpol said.

"The suspect shot at us first, prompting me to spring behind an electric pole and shoot back twice... We had to shoot in self-defence," Hanpol said, insisting that the suspect would not have been harmed if he had not shot at the officers.

Hanpol said investigations had found that "Wichai" was in fact a Hmong man named Wa Saeli from Phetchabun. He had allegedly carried the heroin from the North to be delivered to a Haw person at the dimly-lit spot where he was reportedly gunned down.

About 3,000 people were murdered during the first round of the Thaksin administration's "war on drugs' over three months in early 2003. Some of the deaths were attributed to "silence killings" by people in the narcotics trade, but hundreds of others were regarded as extra-judicial killings by law and security officers.