At least 10 people, including a police officer, have been killed in a shooting at a supermarket in Boulder, Colorado.
A suspect injured at the scene has been arrested.
Local authorities in the US held a news conference hours after the shooting today.
Police said they had few immediate details of the shooting and no known motive for the violence, which unfolded about 3pm (local time) at a King Soopers grocery store in the Table Mesa area of Boulder, a city at the eastern foot of the Rocky Mountains about 45km northwest of Denver.
Boulder Police Chief Maris Herold said 10 people died in the attack at King Soopers grocery. Among them were 51-year-old police officer Eric Talley, who she said was the first to respond to the shooting, about two miles (over 3km) from the University of Colorado's flagship campus.
Boulder County District Attorney Michael Dougherty said the number of dead was known to law enforcement and would be made public later.
Yamaguchi said the person taken into custody was believed to be the only individual with injuries who survived the bloodshed. He gave no details about the suspect.
Video footage from the scene broadcast by local television stations showed a shirtless, bearded man in boxer shorts being led away from the store in handcuffs, before he was placed on a stretcher and loaded into an ambulance. The man in custody appeared to have a bloody leg and was limping as he walked.
Yamaguchi also said that a second incident reported by police at an apartment building 5km away as being possibly connected to the supermarket shooting turned out to be unrelated.
The bloodshed marked the second deadly US mass shooting in a week, following gun violence last Wednesday that left eight people dead, including six Asian women, at three locations in and around Atlanta. A 21-year-old man has been charged with those killings.