Islamic State adds the Las Vegas mass shooting to a growing list of dubious terror attack claims
Without providing any evidence to support the claim, the Islamic State group on Monday said the gunman in the mass shooting in Las Vegas was "a soldier'' from its ranks who had converted to Islam months ago.
Authorities have yet to identify a motive for the shooting, and said initially there was no evidence of any connection to international terrorism.
The extremist group's Aamaq news agency used to be a relatively reliable source of information, but in recent years has made increasingly exaggerated or false claims.
Earlier this year, it claimed an attack on a casino in the Philippines that turned out to have been a botched robbery carried out by a heavily indebted gambling addict.
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Aamaq released two brief statements hours after the shooting at a country music concert that killed at least 59 people and wounded more than 500. The group later released Spanish language versions of these statements.
In a third statement released hours later, Isis name the purported attacker as "Abu Abd el-Bar al-Amriki (the American)'', saying he responded to calls by the group's top leader Abu Bakr al-Baghdadi to "target the countries of the Crusader coalition'' battling the extremist group in Iraq and Syria.
It added that he caused 600 casualties before he exhausted his supply of ammunition and "martyred'' himself.
Police have identified the shooter as Stephen Craig Paddock, 64, of Mesquite, Nevada, and have said he killed himself after the shooting.
Authorities have not commented on his religious background or said what might have motivated the attack.
Most Isis attacks have been carried out by much younger men.
Sheriff Joseph Lombardo said authorities believe it was a "lone wolf'' attack, and the US Homeland Security Department said there was no "specific credible threat'' involving other public venues in the US.
The extremist organisation 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.
The Isis group does not claim credit for every attack but often claims the ones by individuals inspired by its message but with no known links to the group.
Before Sunday, the deadliest mass shooting in modern US 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 Isis and it claimed the attack.
However, when Isis claimed the attack on a casino in the Philippines that killed dozens of people, it was later left embarrassed when police later identified the attacker as a Filipino gambling addict who was US$80,000 in debt, saying it was a botched robbery that was not terrorism-related.
As The Atlantic reports: "A false claim of credit in Las Vegas will effectively shred the Islamic State's news agency's credibility. It will become a news agency that was once reliable, and now associates itself indiscriminately with heavily armed people in casinos".