WASHINGTON — Nine Republican senators on Friday asked the Trump administration to review a decision that allowed the sale of devices that turn a semiautomatic weapon into essentially a fully automatic firearm.

The lawmakers, including the No. 2 Senate Republican, John Cornyn of Texas, wrote a letter to the Bureau of Alcohol, Tobacco, Firearms and Explosives asking for the agency to examine an Obama administration decision allowing the sale of “bump stock” devices, which allow more rapid firing, and issue its own interpretation.

The request comes after a mass shooting in Las Vegas on Sunday in which the gunman, who killed 58 people, had weapons in his hotel room that were modified with a bump stock.

Products to modify semiautomatic firearms are legal, but a growing number of Republicans have said they’re open to regulating the devices.

The National Rifle Association, the nation’s largest gun-lobbying group, has said bump stocks should be subject to new regulation.

Seeking an administrative review could delay efforts to change the law, or allow lawmakers to argue that legislation isn’t needed.

“The tragic events in Las Vegas brought to light an issue from this past administration that we respectfully request that your bureau swiftly review,” the lawmakers wrote to the ATF acting director, Thomas Brandon.