No fewer than 20 people were killed by a gunman armed with a rifle at a Walmart in El Paso, Texas, on Saturday.
He also wounded more than two dozen before being arrested, authorities said, after the latest U.S. mass shooting sent panicked shoppers fleeing.
Many of those in the busy store were buying back-to-school supplies when they were caught up in the rampage, which came just six days after a teenage gunman killed three people at a food festival in Northern California.
Announcing the death toll at a news conference, Texas Governor Greg Abbott said it was “one of the deadliest days in Texas history.”
Mexico’s President Manuel Lopez Obrador said three Mexicans were among the dead and six were among the wounded. It was the eighth worst mass shooting in modern U.S. history, after the 1984 shooting in San Ysidro that killed 21 people.
The suspect was identified as a 21-year-old white male from Allen, Texas, a Dallas-area city some 650 miles (1,046 km) east of El Paso.
Asked during a CNN interview about reports of disturbing social media posts apparently made by the suspect, Texas Attorney General Ken Paxton said he would not be surprised in any way.
“I think those can help shed light on why he did it,” Paxton said. “They are still interviewing him.”
El Paso police chief Greg Allen said authorities had a manifesto from the suspect that indicates “there is a potential nexus to a hate crime.”
The suspect was taken into custody without incident, according to authorities.
Citing a law enforcement source, El Paso television station KTSM published on its website what it said were two photos of the suspect taken by security cameras as he entered the Walmart.
The images showed a young white man wearing glasses, khaki trousers and a dark T-shirt, and pointing an assault-style rifle. He appears to be wearing headphones or ear defenders.
The images could not be immediately verified, according to Reuters.
U.S. President Donald Trump said on Twitter that the reports from El Paso were “very bad, many killed.”
University Medical Center of El Paso received 13 patients, including one who died, hospital spokesman Ryan Mielke told CNN.
Some of the patients were in surgery while others were in stable condition, he added.
Two of the patients who arrived at the hospital were children with non-life threatening injuries who were transferred to El Paso Children’s Hospital, he said.
Local media said there was such an overwhelming response to an appeal by the police department for blood donations to help the wounded that long lines formed at medical centers, some of which had to tell would-be donors to come back on Sunday.