At least 58 people were killed and 515 others were injured in a mass shooting on the Las Vegas Strip late Sunday night, Las Vegas Sheriff Joseph Lombardo told reporters Monday. It was being described as the deadliest mass shooting in United States history.

Gunfire broke out at 10:08 p.m. Sunday at the Route 91 Harvest festival, Lombardo said. A suspect on the 32nd floor of the Mandalay Bay Hotel & Casino opened fire. When officers breached the room, “He had killed himself,” the sheriff said. This morning authorities identified the suspected shooter as 64-year-old Stephen Craig Paddock of Mesquite, Nevada.

Lombardo called the shooter a “lone wolf” and said no other suspects were believed to be on the loose. At least one off-duty Las Vegas Metropolitan Police Department officer at the concert was killed, the sheriff said. One off-duty member of the Los Angeles Police Department attending the concert was struck by gunfire but was expected to make a full recovery, according to an LAPD statement.

In its own statement, the Bakersfield Police Department said several officers were off-duty attendees. One sustained non-life-threatening injuries, according to the department.

The Las Vegas sheriff would not go into possible motives. Authorities today, however, did say they believed the attack was not connected to any international terrorist groups.

The Route 91 Harvest festival is a 25,000-capacity, three-day country music concert at Las Vegas Village, which is across the street from Mandalay Bay Hotel & Casino. In a statement this morning, Las Vegas Metro police said about 22,000 people were believed to be at the concert last night.

Witnesses' video from the festival appears to capture the sound of automatic gunfire. “The shots just kept coming,” a concertgoer witness told CNN.

Damon Schilling, a spokesman for private medical transport firms AMR and Medic West, said the firms requested extra personnel and ambulances from northern Arizona, San Bernardino County and Los Angeles County in order to deal with the mass casualties.

Las Vegas McCarran Airport tweeted that some flights have been diverted as a result of the nearby police activity.

Associated Press reported that singer Jason Aldean was performing at Route 91 Harvest when shots rang out. “It sounded like machine guns,” a witness told CNN.

Another bystander told a CNN reporter that his friends “are dead.”

The sheriff said anyone with pertinent video of the shooting should bring it to investigators at the Las Vegas Metropolitan Police Department.

Updated throughout at 10:50 a.m. Monday, Oct. 2, 2017, with the latest casualty numbers and details.

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