The ISIS terrorist organization has claimed responsibility for the deadliest mass shooting attack in US history.

50 people were murdered and more than 400 were wounded when a gunman opened fire at a country music concert at the Mandalay Bay resort just before 10:30 p.m. local time

"The Las Vegas attacker is a soldier of the Islamic State in response to calls to target coalition countries," the terrorist organization said.

ISIS also claimed that the shooter "converted to Islam several months ago."

Police identified the gunman as 64-year-old Stephen Paddock, a resident of Mesquite, Nevada.

Police say Paddock had a criminal record, but no known ties to terrorism.

While initial reports claimed Paddock was a recent convert to Islam, Clark County Sherrif Joseph Lombardo said he had no knowledge of Paddock's religious beliefs.

Paddock killed himself before police could apprehend him.

US officials dismissed ISIS' claim of responsibility for the shooting. The officials stated that there was no evidence Paddock had any connection to extremist groups.

The FBI has determined that Paddock had no connections to any foreign terrorist organizations, including ISIS.