Updated at 9:36 p.m. Aug. 3.
White House Bureau Chief Steve Herman contributed to this report.
Twenty people were killed, 26 were wounded and one suspect was in custody after a mass shooting Saturday at a shopping mall complex in the border town of El Paso, Texas, police said.
Police Chief Greg Allen said the victims ranged in age from 2 to 82, according to local media. Mexico's Foreign Ministry said three of the dead and six of the wounded were Mexican nationals.
Law enforcement officials identified the suspect as Patrick Crusius, 21, a white male from Allen, Texas, a northern suburb of Dallas about 1,000 kilometers (620 miles) east of El Paso.
Hate crime investigation
Police said the shooting was being investigated as a hate crime.
"Right now we have a manifesto from this individual that indicates to some degree it has a nexus to potential hate crime," Allen said during a news conference Saturday evening.
A "manifesto," purportedly written by Crusius, was posted online about an hour before the shooting and included language that complained about the "Hispanic invasion" of Texas. The author of the manifesto wrote that he expected to be killed during the attack.
NBC News reported that law enforcement officials learned of the extremist manifesto about an hour before the shooting occurred.
Texas Governor Greg Abbott, who traveled to El Paso, told reporters, "We as a state unite in support of these victims and their family members. ... We pray that God can be with those who have been harmed in any way and bind up their wounds."
Police began receiving calls about 10:39 a.m. local time with multiple reports of a shooting at a Walmart store and the nearby Cielo Vista Mall complex on the east side of the city.
Sgt. Robert Gomez, a spokesman with the El Paso Police Department, said most of the shootings occurred at the Walmart, where there were more than 1,000 shoppers and 100 employees. Many families were taking advantage of a sales-tax holiday to shop for back-to-school supplies, officials said.
"This is unprecedented in El Paso," Gomez said of the mass shooting and multiple injuries, many of which he said were life-threatening.
El Paso Mayor Dee Margo told CNN, "This is just a tragedy that I'm having a hard time getting my arms around."
Originally, Margo, as well as several witnesses, said there were several shooters involved. But police said they thought there was just one shooter.
"I can confirm that it is a white male in his 20s," police spokesman Gomez said. "We believe he's the sole shooter."
Gomez said an assault-style rifle was used in the shooting.
The El Paso shooting was the nation's 249th mass shooting this year, according to the Gun Violence Archive. The archive defines a mass shooting as four or more people shot or killed, excluding the gunman, at one location.
White House
A White House spokesperson said President Donald Trump, who was spending the weekend at his New Jersey golf club, had been briefed on the shooting and had been in contact with Texas’ governor.
Later, Trump tweeted: "Working with State and Local authorities, and Law Enforcement. Spoke to Governor to pledge total support of Federal Government. God be with you all!"
Democratic presidential candidate Beto O'Rourke, who formerly represented the El Paso district in the U.S. House, was at an event in Las Vegas when he heard of the shooting. "I just ask for everyone's strength for El Paso right now — everyone's resolve to make sure that this does not continue to happen in this country," he said, adding he was immediately returning home to El Paso, where his family lives.
Saturday's shooting came less than a week after a mass shooting at a festival in Gilroy, California, where three people, including two children, were killed and 13 others were injured. It was also the second fatal shooting in less than a week at a Walmart store. A gunman shot and killed two people and injured two others Tuesday in Mississippi, before he was shot and arrested by police.
El Paso, a city of about 680,000 people in western Texas, shares the border with Juarez, Mexico.
