LOS ANGELES (AFP) - A shooting and stabbing at a large motorcycle show in the western US state of Colorado has killed one person and injured at least six others, officials said Saturday (Jan 30).

The early afternoon incident in Denver prompted a precautionary lockdown at a local hospital where the wounded were taken.

"During the disturbance, there were shots fired and at least one stabbing," Denver police spokeswoman Raquel Lopez told reporters.

"We do have one deceased party and multiple other victims. At this time, we do not have anyone in custody." The Denver Post, describing the incident as a "shooting/stabbing melee," cited an anonymous witness as saying that the feud was started by rival biker gangs.

The newspaper said the witness asked not to be named out of fear of retaliation.

Lopez could not confirm that biker gangs were involved, saying an investigation into the incident was ongoing.

The Denver Health Medical Center said its paramedics brought in seven people - including one deceased.

Of the six injured, three were in critical condition and three in serious condition, it said.

It temporarily went into lockdown mode as a precaution but tweeted in the late afternoon that it had returned to normal operations.

The Colorado Motorcycle Expo, held Saturday through Sunday at Denver's National Western Complex, bills itself as one of the largest motorcycle events in the country.