A shooting occurred at the Route 91 Harvest Country Music Festival in Las Vegas on Sunday night, killing at least 50 people and wounding 400 making it the deadliest mass shooting in modern U.S. history.

The gunman, identified as 64-year-old Stephen Paddock was perched on the 32nd floor of the Mandalay Bay Hotel and Casino when he opened fire on the sold out concert grounds that holds approximately 40,000 people. At the time of the shooting, there were 22,000 people in attendance.

Once officered were able to force entry into his hotel room with explosives, they discovered more than 10 rifles and believe Paddock had shot himself before they could enter the room.

At first, many thought the gunfire had been something else, such as fireworks or glass breaking, which caused the performance by Jason Aldean to pause, which then was interrupted by another shower of gunfire and muzzle flashes from the hotel above. Many fled and took cover behind concession stands and under parked cars.

Police in Las Vegas shut down Las Vegas Blvd. and authorities across the state and federal ranks converged at the scene of the shooting. Interstate 15 and flights at McCarran International Airport were briefly closed, as ambulances and others with cars assisted with transporting the wounded to hospitals.

Some who were out on the street at the time can recall seeing "armoured personnel vehicles, SWAT vehicles, ambulances, and at least a half-mile of police cars," littering the streets.

Among those killed were two off-duty police officers who were attending the concert and two on-duty officers who were wounded. Jason Aldean and his crew were able to get themselves to safety and took to social media to offer his condolences writing, "It hurts my heart that this would happen to anyone who was just coming out to enjoy what should have been a fun night," and also posted on Instagram, calling the shooting "beyond horrific."

President Trump was also briefed on the attack, and wrote a tweet to offer his condolences to the victims and their families, "My warmest condolences and sympathies to the victims and families of the terrible Las Vegas shooting. God bless you!" he wrote.

This is the third tragedy to occur at a concert in recent years. This attack occurred "more than four months after a suicide bombing at an Ariana Grande concert in England, and the November 2015 gunfire that occurred at the Bataclan concert hall in Paris.

Paddock's family was shocked to discover he was behind the attack, his brother said in a telephone interview that they "are horrified," and had no idea. He then offered his sincere condolences to the victims and their families. Police have also said Paddock was not known to police, he had no criminal record, and they do not yet know the motive for the attack and believe he is not connected to any militant group.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.