Ten people have been killed, including a 'hero' police officer, after a gunman opened fire in a horrifying massacre at a supermarket in the US.
In dramatic footage a bloodied man was seen being led away by officers amid initial reports that someone had been gunned down in Boulder, Colorado.
Panicked shoppers and eyewitnesses spoke of their terror as shots rang out at a King Sooper grocery store with people running for cover.
Ten people were later confirmed dead in the slaughter, and among those killed was the first officer on the scene.
He was named as Officer Eric Talley, 51, described as 'heroic' by colleagues and whose 'life was cut much too short.'
The father of seven was devoted to his family and his job, his father Homer Talley said.
“He took his job as a police officer very seriously," Mr Talley wrote in a statement.
"He had seven children. The youngest is 7 year old. He loved his kids and his family more than anything.
"He joined the police force when he was 40 years old. He was looking for a job to keep himself off of the front lines and was learning to be a drone operator.
"He didn’t want to put his family through something like this and he believed in Jesus Christ."
The suspect in the mass shooting has not been named but is currently in custody, and reportedly seriously injured.
The bloodshed comes just a week after shocking violence left eight people dead, including six Asian women, at three locations in and around Atlanta.
It is the deadliest in the US since a disgruntled worker killed 12 people in a shooting spree hours after being sacked before he was shot himself, in Virginia Beach in May 2019.
Outlining Monday's shooting in Boulder, Colorado, police said they were first called to the "active shooter" incident at a grocery store.
Aerial footage broadcast live from the scene showed one person being placed in an ambulance and a bloodied man being escorted away in handcuffs.
People were filmed lying motionless in a car park after shots were fired in a supermarket at about 2.30pm local time (8.30pm GMT).
A Twitter alert from police said the incident unfolded at a King Soopers grocery store in the Table Mesa area of Boulder, a city 28 miles northwest of Denver.
Officers were called to a report of someone being gunned down in the carpark, according to ABC News, only for a suspect to open fire on them.
One man who said he was shopping inside the store with his wife told KCNC-TV in an on-camera interview that he heard three loud bangs he took for gunshots, and ran through the store with other customers to escape through a loading bay at the rear of the building.
Eyewitnesses described chaotic scenes as many ran for their lives on hearing the multiple gunshots ring out.
"I just nearly got killed for getting a soda and a bag of chips," Ryan Borowski, who was in the store when he heard at least eight gunshots and escaped, told CNN.
"It felt amazing that everybody was helping each other out and that our instincts were on the same page and we ran... I don't know why other people didn't, and I'm sorry that they froze. I wish that this just didn't happen."
Andy Arellano, a store employee, told KMGH he was concerned for his co-workers and shoppers as shots rang out.
"We were like sitting ducks, you know, and that's one thing that I'm reliving it and looking at it in my head. And that, that bothers me, I'm still shivering, I'm still shaking," he said.
Sarah Moonshadow, another eyewitness, told the station she was in the supermarket with her son when she heard four gunshots.
"We were hiding down, kind of in the self-checkout area, and I just knew like this is a problem, and I started counting in between shots and then I just grabbed Nicholas, I said, 'Move now.'"
Photographs of a man wearing only underwear with blood trailing down his leg while he is walked away by police circulated on social media.
Several minutes after he was taken away a line of people could be seen leaving surrounded by officers.
A Boulder Community Health spokesman, Rich Sheehan, said one person taken by ambulance to the hospital from the supermarket was undergoing medical treatment, but declined to describe the nature of injuries or the patient's condition.
Dean Schiller, who described himself as a journalist and who was live-streaming footage from the scene for a YouTube channel identified as ZFG Videography, said in interviews with local media he heard what sounded like gunshots as he exited the grocery store.
Highlighting the seriousness of the shooting US President Joe Biden was said to have been 'briefed' on the incident.
His press secretary Jen Psaki said as the incident unfolded: "The President has been briefed on the shooting in Colorado and he will be kept up to date by his team as there are additional developments."
