The Islamic State claimed responsibility for the Las Vegas shooting, in which at least 59 were killed and 525 wounded on Monday when a gunman opened fire at a Las Vegas music festival. The FBI, however, said the shooter had no connection to an international terrorist group.

The gunman, Stephen Paddock, 64, perched high on the 32nd floor of a Las Vegas Strip hotel, unleashed a shower of bullets down on an outdoor music festival below, as tens of thousands of frantic concert-goers screamed and ran for their lives, officials said Monday. Police confirmed that Paddock killed himself before police could apprehend him.

This was the deadliest mass shooting in modern U.S. history.

"The Las Vegas attack was carried out by a soldier of the Islamic State and he carried it out in response to calls to target states of the coalition," the group's news agency Amaq said in reference to the U.S.-led coalition fighting the group in the Middle East.

Las Vegas shooter, identified as Stephen Paddock, 64, converted to Islam months ago, said the Islamic State's Amaq news agency.

Open gallery view A map of the scene of the attack. Credit: Haaretz Infographics

Two senior U.S. officials said that at this time, there is no evidence that the Las Vegas shooter was connected to any international militant group. ISIS often claims attacks by individuals inspired by its message but with no known links to the group.

>> Las Vegas shooting won’t change America’s demented love for weapons of mass killing | Analysis

Las Vegas authorities were reportedly already on high alert before the massacre on the Vegas Strip Sunday night after ISIS released a propaganda video earlier this year showing footage of the site. According to Newsweek, "The 44-minute-long video released in May showed footage of the Las Vegas strip from 2015, calling on its supporters to conduct attacks with knives and vehicles."