Investigators have still not found a motive for the Las Vegas shooting rampage that killed 58 people, Undersheriff Kevin McMahill has said.

The Clark County official said the authorities have looked at gunman Stephen Paddock’s personal life, political affiliation, economic situation and any potential radicalisation.

He said investigators are aware the Islamic State group has claimed responsibility for the attack, but so far there is no evidence that it had a role.

Graphic released by Amaq <a href=News Agency, a media arm of the Islamic State group, claiming responsibility for the mass shooting in Las Vegas">Graphic released by Amaq News Agency, a media arm of the Islamic State group, claiming responsibility for the mass shooting in Las Vegas (Amaq News Agency via AP)

Mr McMahill said the authorities will continue to investigate those areas as well as look into leads and tips that come in.

Paddock unleashed gunfire on Sunday from the 32nd floor of the Mandalay Bay hotel casino on the Las Vegas Strip, killing 58 and injuring nearly 500 people.

He killed himself as police closed in.