When a street vendor at Justin Herman Plaza tried to stop a dispute between skateboarders near his booth Friday, “fearing that his items would be affected,” the skaters turn on him and other vendors in the area creating a bloody melee, according to police. The brawl along the Embarcadero at 5:30 p.m. was caught on video showing a violent confrontation that involved chairs, a hammer, skateboards and easel. The skateboarders then appear to use their decks, fists and the vendors’ displays as weapons, while some vendors fight back. At one point, a street vendor holding a hammer was chased by several youths wielding skateboarders. “Put that hammer down,” one skateboarder yells. The other accuses a street vendor of hitting him with a hammer, before the fight escalates. Two of four street vendors — aged 36, 46, 58 and 61 — were transported to the hospital after the brawl broke up, Officer Carlos Manfredi said. The four sustained injuries including lacerations to the eyes and pain to the hand and face. Video showed what appears to be the bloody chin of a vendor after a skateboarder slugged him in the face. The skateboarders fled the scene before police arrived, though officers responded to an initial witness report of a “mass riot” from both Central and Southern stations, Manfredi said. Police are seeking two suspects in the incident described at black males, one aged 18 to 20 and the other 20 to 25. Skateboarders can often be seen gathered around the median at Justin Herman Plaza, a foot-traffic heavy intersection at the end of Market Street with a Muni bus turnaround.