WASHINGTON — The National Rifle Association joined the Trump administration and top congressional Republicans Thursday in a swift and surprising embrace of a restriction on Americans’ guns, though a narrow one: to regulate the “bump stock” devices the Las Vegas shooter apparently used to horrifically lethal effect.

The devices, originally intended to help people with disabilities, fit over the stock and grip of a semi-automatic rifle and allow the weapon to fire continuously, some 400 to 800 rounds in a single minute. Bump stocks were found among the gunman’s weapons and explain why victims in Las Vegas heard what sounded like automatic-weapons fire as the shooter rained bullets from a casino high-rise, slaughtering 58 people in a concert below and wounding hundreds more.

Thursday’s sudden endorsements of controls came almost simultaneously from the NRA and the White House. The NRA, which famously opposes virtually any hint of new restrictions, said in a statement: “The National Rifle Association is calling on the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) 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.”

Moments after, at the White House, press secretary Sarah Huckabee Sanders praised the announcement. “We welcome that and a conversation on that,” Sanders said. “It’s something we’re very open to.” House Speaker Paul Ryan added his support, as have other top Republicans.

“Obviously we need to look at how we can tighten up the compliance with this law so that fully automatic weapons are banned,” the Wisconsin Republican told reporters at an event in Chestertown, Maryland.

It was a rare concession for all concerned. The nation’s largest gun lobby and most Republicans have stood firmly in recent years against stricter gun regulations, even as one mass shooting after another horrified the nation. They blocked background check legislation after the shooting deaths of elementary school children in Connecticut in 2012, and took no action despite intense pressure from Democrats.