Six men believed to be wearing stolen police uniforms opened fire with assault rifles at a pool hall in the gang-plagued Caribbean coastal city of San Pedro Sula, killing eight people.

The shots were fired from a vehicle parked outside the pool hall on Sunday, said Edgardo Villeda, police assistant commissioner. The eight victims included one woman.

"It all happened very quickly. It was a cold-blooded killing. The victims didn't have time to react," Villeda said. "We don't think it was done by policemen, but rather by people who have taken our uniforms."

Initial investigations suggest the men may have been members of one of the street gangs that have carried out killings of rival gang members in the past. The Mara Salvatrucha and rival Mara 18 gangs, comprising about 100,000 members, control poor neighborhoods in Honduras' main cities with violence, threats and extortion.

They also have attacked police, stealing uniforms and firearms.