At least 10 people, including a police officer, were killed when a gunman opened fire at a grocery store in the US state of Colorado, authorities said, adding that a suspect was in custody. The shooting took place on Monday at the King Soopers grocery store in the city of Boulder.
Addressing a press conference, Boulder Police chief Maris Herold said that the officer, identified as 51-year-old Eric Talley, was one of the first responders at the scene, DPA news reported.
She called his actions "heroic".
Herold said that police began receiving calls about shots fired and a call about a person with a "patrol rifle" at around 2.30 p.m.
Talley was one of the first officers at the scene and was "fatally shot."
"This is a very complex investigation that will take no less than five days to complete," Herold said at the conference.
"We have multiple people who were killed in this incident. And I am sorry to have to report that one of them was a Boulder police officer," said Kerry Yamaguchi, police commander.
Multiple US media reports said around six people were executed in the shooting, citing anonymous law enforcement sources. A video clip that streamed earlier showed a white middle-aged man - shirtless and covered in blood, arrested by the police and was led from the supermarket.
The suspect in custody was the only person suffering "serious injuries at this point," Yamaguchi said, without confirming that the man in the video was that suspect.
CNN cited an unnamed senior law enforcement source as saying that the weapon used in the shooting was an AR-15-style rifle.
Police said that the names of the victims would not be released until their families are notified.
The Boulder Police Department tweeted an alert about an "active shooter" at a grocery store at around 2.50 p.m.
Police said officers arrived at the scene "within minutes" of receiving a 911 call and entered the building "very quickly."
Boulder County District Attorney Michael Dougherty said that the "alleged shooter" was injured and in custody.
The Boulder Police Department also confirmed that there was "no ongoing public threat".
In a tweet, Colorado Governor Jared Polis said: "My prayers are with our fellow Coloradans in this time of sadness and grief as we learn more about the extent of the tragedy."
The White House confirmed that President Joe Biden has been briefed about the carnage.
Next mass shooting
Last week, a mass shooting at Asian-owned spas in the southeastern state of Georgia in which 8 people were killed.
Previously, Colorado had witnessed two of the most infamous mass shootings in US history. In 1999, two teenage boys shot and killed 12 classmates and a teacher at Columbine High School before dying by suicide. In 2012, a heavily armed man charged a movie theatre showing a Batman film in Aurora, Colorado, butchering 12.
Last month, President Biden said he wants Congress to pass laws that would need a background check on the sale of all guns and ban assault weapons and high-capacity magazines.
"This administration will not wait for the next mass shooting to heed that call," Biden said.