Las Vegas, Oct 2 (Zee News): The Islamic State group on Monday claimed responsibility for the mass shooting at a Las Vegas music concert in which at least 50 people were killed and over 400 injured, a media report said.

Citing an ISIS propaganda agency, the AFP reported that the terror outfit has claimed responsibility for Sunday night's horrific attack.

"The executor of the Las Vegas attack is a soldier of the Islamic State," the news agency quoted ISIS propaganda outlet Amaq as saying.

The attacker carried out the operation as a "response" to calls to target countries engaged in military action against jihadists, Amaq said but provided no evidence to back its claim.

The fatalities took place when 64-year-old Stephen Paddock opened fire on a crowd at a music festival from a nearby hotel. The police shot him dead.

An initial probe shows Paddock was travelling with a female companion named Marilou Danley hours before the attack. A search is currently on to nab Danley.

Paddock lived in a two-bedroom home in Mesquite, Nevada, some 80 miles from Las Vegas, police said.

The suspect's brother, Eric Paddock, said the family was stunned by the news.

Police said Paddock may have acted on his own as he was not found to be connected with any terror organisation.

Authorities have also found several weapons in Paddock's hotel room on the 32nd floor of the Mandalay Bay Resort and Casino after the Sunday's mass shooting, considered deadliest in modern US history.