The man behind the worst mass shooting in modern US history had an arsenal of at least 42 guns, explosives and several thousand rounds of ammo, police said.

Officers recovered 19 firearms, explosives and ammo from Stephen Paddock’s home in Mesquite, Nevada, hours after discovering 23 guns in the Las Vegas hotel room from which he killed at least 59 concertgoers.

Earlier, police found several pounds of ammonium nitrate, a chemical used to make explosives, in the 64-year-old’s car.

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Some of the firearms recovered from his hotel room had scopes, while two were reportedly modified to make them fully automatic.

Las Vegas Police Department said officers were searching another home owned by Paddock in Reno, Nevada, adding that authorities were still unclear about the gunman’s motive.

I can’t get into the mind of a psychopath at this point, sheriff Joe Lombardo said.

Detectives have described Paddock as a lone wolf and dismissed speculation there were more assailants.

SWAT teams found the retired accountant dead in his room on the 32nd floor of the Mandalay Bay hotel.

Paddock’s brother said he was not an avid gun guy and claimed he had become a multi-millionaire through real estate investments.

In a televised address, President Donald Trump described the shooting as an act of pure evil but did not make reference to a growing row over Americans’ right to bear arms.

White House press secretary Sarah Huckabee Sanders later told reporters that it was premature to discuss tighter gun regulations.

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British Prime Minister Theresa May told Sky News she had spoken with Mr Trump, and described the attack as completely senseless and cowardly.

Mr Trump will visit Las Vegas on Wednesday to grieve with the friends and family of the victims, offer his support to those recovering from wounds and thank courageous first responders, Ms Sanders added.

City officials have made an urgent appeal for blood donors as at least 527 people who were injured in the shooting are treated in hospitals across Nevada.

Some of those wounded were hit by shrapnel, while others were trampled on as hundreds fled the concert in panic.

After visiting a hospital in Las Vegas, congressman Ruben Kihuen said: Literally, every single bed was being used, every single hallway was being used. Every single person there was trying to save a life.
(c) Sky News 2017: Las Vegas shooting: Gunman Stephen Paddock ‘had 42 guns and explosives’