Two are being sought following a shooting at a school bus stop in Las Vegas.
Six people were injured, two critically, when gunmen opened fire as students were getting off the school bus.
Clark County Sheriff Doug Gillespie said the incident appeared to have been sparked by an argument over a girl at a high school earlier in the day.
Two 18-year-olds are in a critical condition following the incident, while four others were released from hospital with minor injuries.
Police initially detained five or six people for questioning but have not arrested any suspects and cannot yet provide a description of the two assailants, other than to say that they were male.
