The National Rifle Association has called for tougher regulations on modification devices that can convert firearms into automatic weapons.
The Las Vegas attacker, Stephen Paddock used "bump stocks" to transform many of his semi-automatic rifles into fully automated rapid-fire guns.
The massacre, in which 58 people died and about 500 were injured, has reignited the debate over America's gun laws.
Regulation
The NRA, which has opposed efforts to pass federal gun legislation following previous mass shootings, said it would not oppose moves to regulate bump stocks.
The influential lobbying group added: "The National Rifle Association is calling on the Bureau of Alcohol, Tobacco, Firearms and Explosives to immediately review whether these devices comply with federal law.
"The NRA believes that devices designed to allow semi-automatic rifles to function like fully automatic rifles should be subject to additional regulations."
Review
The White House has said President Trump would welcome a review of the policy on the devices, which were found on 12 of the nearly 50 firearms amassed by Paddock.
Press secretary Sarah Huckabee Sanders said that "we're certainly open to having that conversation," while House of Representatives speaker Paul Ryan said banning bump stocks is "clearly something we need to look into."
In an interview with MSNBC, he added: "I didn't even know what they were until this week ... I think we're quickly coming up to speed with what this is."
Rapid-fire
Bump stocks were originally intended to help people with limited hand mobility use a semi-automatic weapon without needing to pull the trigger for every round fired.
But with applied pressure, they can cause the weapon to fire continuously.
The rate of fire can increase from between 45 and 60 rounds per minute to between 400 and 800 rounds per minute, according to Democrat senator Dianne Feinstein, who introduced legislation this week to ban them.
The government approved selling the devices in 2010 after judging that they did not violate federal law.
