Islamic State claims Las Vegas mass shooting; provides no evidence

People scramble for shelter at the Route 91 Harvest country music festival after a gunman opened fire on a crowd of 22,000 on October 1, 2017 in Las Vegas, Nevada. (Photo by David Becker/Getty Images)

The Islamic State group on Monday claimed responsibility for the mass shooting in Las Vegas, saying the perpetrator was "a soldier" who had converted to Islam months ago, without providing any evidence to support the claim.

The group's Aamaq news agency released two brief statements hours after the shooting at a country music concert that killed at least 50 people and wounded at least 400. It was the deadliest mass shooting in modern U.S. history.

During a briefing around 8:30 Pacific Time, the FBI said there was no evidence of a connection between the shooter and IS.

RELATED: Gunman kills 50 on Las Vegas strip, 406 injured

IS did not name the suspected shooter, but said he had "executed the operation in response to calls to target countries of the coalition" batting the extremist group in Iraq and Syria. The group later released a Spanish language version.

RELATED: Stephen Paddock: What we know about Las Vegas shooting suspect

Police have identified the shooter as Stephen Craig Paddock, 64, of Mesquite, Nevada, and have said he killed himself after the shooting. Sheriff Joseph Lombardo said authorities believe it was a "lone wolf" attack, and the U.S. Homeland Security Department said there was no "specific credible threat" involving other public venues in the U.S.

The IS group often claims attacks by individuals inspired by its message but with no known links to the group.

RELATED: Man escaped from Las Vegas shooting says gun fire 'just didn't stop'

Before Sunday, the deadliest mass shooting in modern U.S. history took place in June 2016, when a gunman opened fire at a gay nightclub in Orlando, Florida, killing 49 people. The shooter, Omar Mateen, had pledged allegiance to IS and it claimed the attack.

IS claimed responsibility for an attack on a casino in the Philippines that killed dozens of people earlier this year, but police later identified the attacker as a heavily indebted Filipino gambling addict, saying it was a botched robbery that was not terrorism-related.

RELATED: As many as 10 guns found in hotel room of Las Vegas shooter

The extremist organization has suffered a string of major setbacks in Iraq and Syria, where it has lost much of the territory it once claimed as part of a self-styled Islamic caliphate. However, the group remains active in recruiting followers on social media, and has repeatedly called on its supporters to carry out attacks in Western nations.