The powerful National Rifle Association on Thursday backed "additional regulations" on devices that boost semi-automatic weapons' firing rates, like the tools used by the shooter in the Las Vegas massacre.

In a statement, the influential gun rights group's Wayne LaPierre and Chris Cox urged the Bureau of Alcohol, Tobacco, Firearms and Explosives to review the legality of so-called bump stocks. They stopped short of pushing Congress to pass a bill banning or regulating the devices.

"Despite the fact that the Obama administration approved the sale of bump fire stocks on at least two occasions, the National Rifle Association is calling on the [ATF] to immediately review whether these devices comply with federal law," the NRA officials said. "The NRA believes that devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations."

The NRA's support for more regulation of bump stocks could give Republican lawmakers more breathing room to pass a bill regulating them. The group has traditionally resisted any efforts to tighten gun laws.

The statement came as bipartisan momentum for regulating the devices built on Capitol Hill. The White House also indicated that President Donald Trump could be open to discussing changes to bump stock laws.

The NRA also called for Congress to pass a law easing concealed carry laws. Under the legislation, gun owners with a concealed carry permit in one state could legally carry nationally.

Audio of the Sunday night attack on the Route 91 Harvest musical festival in Las Vegas contained rapid-fire bursts into the crowd. Fifty-eight people were killed and hundreds were shot or injured in the stampede to escape.



Investigators said the gunman, Stephen Paddock, had 12 rifles equipped with bump stocks.

House Speaker Paul Ryan said Congress should "look into" whether to make changes around bump stocks. Sen. John Cornyn — the No. 2 Republican in the Senate — on Thursday said "it's worth our serious consideration" to ban the tools.

Asked about the growing momentum for a ban on bump stocks, White House press secretary Sarah Huckabee Sanders said Trump is "open to having that conversation," but stressed that Trump is "a strong supporter of the Second Amendment." She added that any discussion of gun laws is premature.

— CNBC's Christina Wilkie contributed to this report