Trump says they will be talking about gun laws after Las Vegas

A renewed debate on US firearms regulations roared to life as US police continued their search for a motive in the massacre of 59 people at a Nevada music festival.

A gunman rained automatic weapons fire from the 32nd floor of a hotel on the Las Vegas Strip onto 22,000 people attending a country music concert on Sunday night. The deadliest shooting spree in US history left more than 500 people injured.

"We'll be talking about gun laws as time goes by," US President Donald Trump told reporters, on his way to tour hurricane damage in Puerto Rico.

The shooter, identified as Stephen Craig Paddock, 64, killed himself as officers arrived, police said.

Trump, who is due to visit Las Vegas on Wednesday, called the gunman "a sick man, a demented man."

Police found at least 10 rifles in the hotel room of the gunman, who rapidly fired hundreds of rounds into the concert crowd from a distance of some 300 metres. Automatic weapons are generally banned in the United States, but the killer may have illegally altered semi-automatic rifles.

Congressman Chris Murphy, a Democrat from Connecticut, wrote in a Tuesday column in the Washington Post about "mythology spread by the gun lobby" in the United States.

"There is not much real controversy around the first steps we should take to trim rates of gun crime," Murphy wrote.

"Large majorities of Americans support universal background checks, permit requirements for gun ownership and bans on the most dangerous kinds of weapons and ammunition. The gun lobby, and the loud vocal minority it echoes, make the issue seem like more of a hot button than it is."