The nation’s largest gun-lobbying group said devices that allow semiautomatic rifles to function like automatic firearms should be subject to new regulation after a growing number of Republican lawmakers say they’re open to such restrictions.

Following a mass shooting in Las Vegas on Sunday, in which the gunman had weapons modified to allow rapid firing, the National Rifle Association called on the Bureau of Alcohol, Tobacco, Firearms and Explosives to review whether the “bump stock” devices used to modify semiautomatics 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,” the group said in a statement on Thursday. The NRA also criticized politicians seeking to ban guns, saying doing so wouldn’t prevent a “criminal act of a madman.”

For years, Republican lawmakers have been largely in line with the NRA, which has long objected to new restrictions. The shooting in Las Vegas, in which 58 people were killed, has brought new attention to bump stocks, aftermarket accessories that allow more rapid firing, and prompted Republicans’ comments. Many Democrats have long called for much stricter gun laws.

With the NRA and Republicans, who control both chambers of Congress, open to more strict regulation of bump stocks, it stands a good chance of taking affect.

House Speaker Paul Ryan of Wisconsin told MSNBC that changing the law is “something we need to look into.”

“I didn’t even know what they were until this week and I’m an avid sportsman,” Ryan said.

President Donald Trump hasn’t weighed in on the bump stock debate yet and has deflected questions on gun control since the attack.

On Wednesday, Sen. John Cornyn of Texas, the No. 2 Republican leader, said he’s open to considering new limits on bump stocks and called for a hearing. Sen. Ron Johnson, a Wisconsin Republican, called for a ban on the devices.

“My reaction was that this was all designed to kill or injure as many people as possible as quickly as possible, and that’s the reason why automatic weapons are generally not available,” Cornyn said Thursday. “No sportsmen or hunter uses them.”

Sen. James Inhofe, an Oklahoma Republican, said he doesn’t see a need for the devices to be legal but wants to hear more about the accessories before making a final decision. Arizona Republican Sens. John McCain and Jeff Flake made similar comments.

“I’m open to finding out about it and maybe putting it on the category that would be outlawed,” Inhofe said.

Other Republican senators, including Orrin Hatch of Utah and John Thune of South Dakota, said they’re considering whether changes are needed.

Sen. John Barrasso, a Wyoming Republican, said he wants more study of the bump stocks and isn’t ready to call for a ban. “For a guy from Wyoming who owns plenty of guns, it’s something I’d never heard of until yesterday,” he said. “This news is terrible and what’s happened is a great tragedy.”

The NRA statement reiterated its position that “banning guns from law-abiding Americans based on the criminal act of a madman will do nothing to prevent future attacks.” The group also urged Congress to pass legislation that would require states to recognize right-to-carry permits issued by all other states.

Democrats, including Sen. Dianne Feinstein of California, on Wednesday introduced legislation banning aftermarket products designed to allow more rapid firing.

House Minority Leader Nancy Pelosi of California called on lawmakers to add various new restrictions, including bolstered background checks of gun purchasers and a ban on bump stocks.

But Democratic Sen. Claire McCaskill of Missouri said her party should be careful not to push too hard.

“Let’s stay focused on the possible,” she said. Right now, she added, lawmakers in both parties are talking about bump stocks and “I’d like us to stay focused on it.”

Selling and manufacturing automatic weapons has been illegal since 1986, and weapons purchased before then are regulated by the federal government. Products to modify semiautomatic firearms are legal.

Bump stocks “may be an area where we need to look to be sure the law is not being subverted,” said Sen. Roy Blunt, a Missouri Republican.

GOP Rep. Mark Meadows of North Carolina said lawmakers are drafting a letter to ATF seeking more information. Meadows said he doesn’t understand why someone would want to buy one.