Six people were shot dead and five others wounded when gunmen got onto a bus Friday in a town near San Salvador and opened fire on passengers, police said. The attackers, who witnesses said were dressed in road repair workers' uniforms, fled before the police rushed to the scene, investigators said, adding that it was not clear whether they belonged to a gang. The bloodshed occurred amid threats of increased violence in the Central African country, where gang crimes have been rampant over the past years.