Bogota, Jul 2 (IANS/EFE): Five people died and one was wounded when gunmen attacked a bar in Tumaco, a port city in southwestern Colombia, officials said.

Investigators are trying to determine whether the victims belonged to a criminal organization, Tumaco Mayor Victor Gallo told reporters Sunday.

"There are indications that these people belonged to the group of the Los Rastrojos gang," Gallo said.

The victims were talking early Sunday when "several armed people opened fire on them indiscriminately", the mayor said.

The massacre occurred in Bucheli, which is located outside Tumaco, a Pacific port city in Narino province.

Drug traffickers and Revolutionary Armed Forces of Colombia, or FARC, guerrillas operate in the area.

Los Rastrojos is one of a number of gangs founded by veterans of the defunct United Self-Defense Forces of Colombia, or AUC, militia federation.

Los Rastrojos and the other AUC successor groups, such as Los Paisas and Nueva Generacion, are responsible for a good deal of the criminal activity in Colombia, officials say.