At least one person has been killed and several others wounded in a shooting and stabbing melee in the US state of Colorado, a security official says.
According to Denver Police spokeswoman Raquel Lopez, the incident occurred at the National Western Complex near the Denver Coliseum on Saturday evening just before 13:00 local time (20:00 GMT) when multiple shots were fired and at least one person was stabbed.
Denver Health Medical Center reported of nine injured people being treated, three of whom in critical condition.
No one was reported in custody and the hospital was put on lockdown as a safety precaution.
The venue was hosting the Colorado Motorcycle Expo, one of the largest events of its kind in the US.

One witness, who asked to remain anonymous out of fear of retaliation, told the Denver Post newspaper that the feud was started by rival biker gangs.
"In Denver, authorities were still trying to determine which motorcycle gang or gangs were involved," Lopez said.
The gun fight took place during the first day of the annual Colorado Motorcycle Expo, when hundreds of motorcycles were parked near the complex.
Organizers expected nearly 3,000 people to attend over the weekend.
Police said the show would go on as scheduled.
Back in November, three people died and 9 others were injured in a shooting incident in Colorado Springs, Colorado.