DENVER » One person was fatally shot and seven others were injured in a shooting and stabbing at a motorcycle expo today, Denver police said.

Police Chief Robert White told reporters that it was unclear what prompted the incident at the National Western Complex, where the Colorado Motorcycle Expo was being held this weekend. Police were interviewing several witnesses, including those being treated at the hospital, and were also talking to one person of interest, he said.

Investigators believe there was an exchange of gunfire at about 1 p.m. In addition to the person who was shot and killed, three others were shot, another person was stabbed and three others suffered injuries from a fistfight, White said.

A bystander told the Denver Post that the shooting happened near his leather goods company booth. Bob Cook said he heard two shots fired and saw people dive under tables. He said he didn’t hear any arguments before the shooting.

Dr. Kevin McVaney of Denver Health Medical Center said earlier in the afternoon that six people were admitted to the hospital. Three were in critical condition and three were stable, he said.

Police were keeping a heavy presence at the hospital where the injured people were being treated to prevent the incident from spreading from the expo.

Other events associated with the weekend expo have been canceled, White said.

Police spokeswoman Raquel Lopez said she couldn’t say whether the incident was gang related. No arrests have been made.