A shooting at a supermarket in the US state of Texas that left 20 dead is being investigated as "domestic terrorism", officials say.
Law enforcement agencies respond to an active shooter at a Wal-Mart near Cielo Vista Mall in El Paso, Texas. Photo: AFP
A 21-year-old white man was arrested where the attack took place in the city of El Paso, near the US-Mexico border.
Both El Paso Mayor Dee Margo and police chief Greg Allen have confirmed police are investigating an anti-Hispanic racist screed posted online shortly before the shooting.
In it, the poster, who authorities believe may be the shooter, expresses support for the accused gunman who killed 51 people at two mosques in Christchurch.
The man could face federal hate crime and firearms charges which carry a death penalty.
The suspect opened fire on a crowded Walmart with an assault-style rifle and surrendered after being confronted by officers outside the store. Saturday's attack also left 26 injured.
"We're treating this as a domestic terrorist case," US Attorney for the Western District of Texas John Bash told a news conference, saying prosecutors were "seriously" considering the federal charges.
The attack
The shooting, believed to be the eighth deadliest in modern US history, took place in a city where most of the population of 680,000 is of Hispanic descent. It lies along the Rio Grande across the border from Ciudad Juárez in Mexico.
The victims have not yet been named but Mexico's President Andrés Manuel López Obrador said three Mexican nationals were among the dead.
CCTV images said to be of the attacker show an armed man in a dark T-shirt wearing eye glasses and what appears to be ear protectors.
Reports of an active shooter were received at 10:39 local time, and law enforcement officers were on the scene within six minutes, Mr Allen said.
The Walmart, near the Cielo Vista Mall, was full of shoppers buying back-to-school supplies at the time of the shooting, and witnesses described scenes of chaos as customers fled for their lives.
"People were panicking and running, saying that there was a shooter," Kianna Long told Reuters news agency. "They were running close to the floor, people were dropping on the floor."
Ms Long said she and her husband ran through a stock room before taking cover with other customers.
US President Donald Trump called the attack "an act of cowardice" on Twitter: "I know that I stand with everyone in this country to condemn today's hateful act. There are no reasons or excuses that will ever justify killing innocent people."
Dayton shooting
Nine people have also been killed and at least 27 injured in a mass shooting in Dayton, Ohio - only hours after the Texas mass shooting.
People gather for a vigil for the victims of the mass shooting in Dayton, Ohio. Photo: AFP
Footage posted on social media showed people running as dozens of gunshots echoed through the streets.
It is thought the shooting took place outside Ned Peppers Bar on E 5th Street. The bar later posted on social media its staff were safe.
All the fatalities happened outside in the street, police said.
Police confirmed they killed the gunman at the scene within a minute of him opening fire.
The local mayor said the gunman wore body armour and came carrying extra ammunition and used a .223-calibre assault rifle with high-capacity magazines.
Jae Williams told the BBC he was at a nearby rap performance when they were told to evacuate.
"I was very shocked," he said. "We all evacuated quickly and safely. We were told to avoid the Oregon district."
"I got to my car, I could see cops, multiple ambulances."
Another eyewitness told Reuters they had been in a nearby nightclub, Newcom's, when the shooting happened. "The screams, the cruisers, the chaos... the security guards and themselves were running around and telling people to get out and just how everybody was acting, you knew something was wrong," she said.
"And then when you came outside, as soon as you hit the front street, you've seen the bodies, you knew this was different. You knew it was something that you never thought of experiencing, never experienced, wouldn't want anyone to experience."
Assistant Police Chief Matt Carper told reporters that officers managed to take down the gunman.
"Our people are very well trained for a situation like this," he said, adding it was "very fortunate that the officers were in close proximity".
Officially few details have been released and there is no indication yet of any motive. Police said they had identified the attacker, but declined to identify him at a news conference.
On 29 July a gunman opened fire at a food festival in California, killing three people.
- BBC