At least one person has been killed and 22 others seriously injured after a shooting at a Texas shopping centre.
A “white male in his 20s” is in custody after the shooting in the border town of El Paso.
Speaking to reporters, El Paso police Sergeant Robert Gomez said is is likely there would be more deaths to report later, but he could not yet confirm them.
He said most of the shootings happened at a Walmart at the shopping complex.
“This is unprecedented in El Paso,” Mr Gomez said.
Police responded to an active gunman scene at the Cielo Vista Mall and are advising people to stay away from the area and to look for missing family members at a school being used as a reunification area.
Ryan Mielke, a spokesman for University Medical Centre of El Paso, said 12 people were brought to the hospital with injuries, including one that died. Two of the injured were children who were being transferred to El Paso Children’s Hospital.
Eleven other victims were being treated at Del Sol Medical Centre, according to hospital spokesman Victor Guerrero.
Texas governor Greg Abbott called the shooting “a heinous and senseless act of violence” and said the state had deployed a number of law enforcement officers to the city.
A family of three was among a dozen people waiting outside a bus station. They were trying to return to their car that was in a blocked-off Walmart car park.
“I heard the shots but I thought they were hits, like roof construction,” said Adriana Quezada, 39, who was in the women’s clothing section of Walmart with her two children.
Sergeant Enrique Carrillo said by mid-afternoon that a suspect was in custody and the public was no longer in danger.
White House staff said US President Donald Trump was briefed on the shooting and spoke about it with attorney general William Barr and governor Abbott.
“Reports are very bad, many killed,” the president tweeted.
Presidential candidate and former Texas congressman Beto O’Rourke appeared shaken at a candidate forum in Las Vegas shortly after news of the shooting in his home town was reported.
Mr O’Rourke, who said he had called his wife before taking to the stage, said the shooting shatters “any illusion that we have that progress is inevitable” on tackling gun violence.
The Democrat said he heard early reports that the suspect might have had a military-style weapon, saying such firearms should be kept “on the battlefield” and not brought “into our communities”.
Mr O’Rourke said: “We have to find some reason for optimism and hope or else we consign ourselves to a future where nearly 40,000 people a year will lose their lives to gun violence and I cannot accept that.”
El Paso, which has about 680,000 residents, is in West Texas and sits across the border from Juarez, Mexico.