Transcript for Tensions Run High as Gunfire Erupts at Colorado Pot Rally
It was supposed to be mellow and fun. But colorado's first big celebration of legalized weed turned into a scene of gunfire and mass panic. Could this be a setback for the movement to legalize pot in other states? Akiko fujita has more. Reporter: The gunshots turned one of the country's largest pot rallies into a place of panic. And thousands who came to celebrate marijuana in denver, forced to run for cover. Everybody started running and smashing into me. Reporter: Witnesses say as many as ten shots were fired. Three people injured. Police are now searching for two suts but say they don't know what triggered the violence. The event marked the 4/20 counter culture holiday. This was the first since colorado and washington legalized the recreational use of marijuana. The shooting comes at a sensitive time, as colorado lawmakers grappled with how to regulate and enforce use. Recreational use remains illegal under federal law. The question, now, will the large crowds this weekend stall a movement to legalize marijuana? Are they going to play with experiments with regard to have so many folks coming from out of state? Are they willing to regulate those folks the way they regulate they're own citizens? Reporter: Something other states and marijuana supporters will be watching closely. Akiko fujita, abc news, los angeles.
This transcript has been automatically generated and may not be 100% accurate.