Breaking

A gunman opened a barrage of gunfire at a three-day country music festival on Sunday night, sending an armada of people dashing for their lives and leaving over 50 dead and at least 200 victims injured, Las Vegas authorities said. The man, who was at the Mandalay Bay Casino hotel, was found dead by SWAT units.

Multiple online videos with scenes of the incident show a mass of people, frightened and confused, screaming, ducking — running for their lives. One person was heard shouting, “get down,” from a balcony looking over the concert, as multiple rounds of gunfire ricocheted in the chaos.

Just before midnight the Las Vegas Metropolitan Police Department reported that “one suspect is down.” Soon after, police said they believe that the gunman acted alone. The first report of the shooting came at 10:08 p.m. Sunday.

Otro ángulo de la balacera en #LasVegas. Impactantes imágenes. pic.twitter.com/4YIVng1zrP

— Gusini Solano (@GusiniSolano21) October 2, 2017

Sheriff Joseph Lombardo of Clark County told reporters early Monday morning that more than 50 people were killed and more than 200 injured. He identified the gunman as Stephen Paddock, 64. He said the police were seeking “a companion” named Marilou Danley, a woman he described as Asian and 4-foot-11, according to the New York Times.

The Islamic State claimed that Mr. Paddock was one of its soldiers, but did not provide any evidence of its claim. The F.B.I. said there was no evidence so far that Mr. Paddock had ties to any international terrorist organization, and relatives said he had not displayed strong political or ideological beliefs in their interactions with him.

Speaking at the White House, President Trump condemned the shooting as an “act of pure evil” and called for the country to come together, saying, “Our unity cannot be shattered by evil, our bonds cannot be broken by violence.”

The police found an arsenal in the gunman’s hotel room.

At least 23 firearms, including a handgun, were found in Mr. Paddock’s hotel suite, according to the Las Vegas Metropolitan Police Department. Some were rifles equipped with scopes, said Sheriff Joseph Lombardo of the Police Department, adding that Mr. Paddock used multiple rifles during the attack, according to The Times.

A federal law enforcement official earlier said there were at least 20 rifles in the suite, along with hundreds of rounds of ammunition, including two rifles outfitted with scopes and set up on tripods in front of two big windows. Another official said that among the weapons were AR-15-style assault rifles. Both officials spoke on the condition of anonymity because they were not authorized to divulge details of the investigation.

The Mandalay Bay Casino hotel itself was placed on lockdown after the shooting, guests said.

“We went into the hotel and they started shutting down casinos,” Todd Price, a guest of Mandalay Bay, told CNN. “We tried to get into our rooms, and they shut down the elevators and started to get everybody out.”

#BREAKING VIDEO: Jason Aldean on stage as a gunman begins to fire upon crowd in Las Vegas pic.twitter.com/lfWiVaYaBD

— Al Boe BREAKING NEWS (@AlBoeNEWS) October 2, 2017

According to The Times, the Route 91 Harvest Festival bills itself as “three days of country music on the Vegas Strip,” and Sunday night’s performance was the last of the festival. The site of the concert, the Las Vegas Village and Festival Grounds, run by MGM Resorts, sprawls over 15 acres and has a capacity of 40,000 people. The festival’s website said this year’s three-day concert was sold out.

The incident is one of the deadliest mass shootings in United States history.

This is unbelievable! Las Vegas Blvd is shut down at Tropicana! Avoid all areas near #MandalayBay! Active shooter near Route 91 festival! pic.twitter.com/1ybPgr0ofd

— E5QUIRE (@Dj_E5QUIRE) October 2, 2017