WASHINGTON — The National Rifle Association announced its support Thursday for regulating “bump stocks,” devices that can effectively convert semi-automatic rifles into fully automated weapons and that were apparently used in the Las Vegas massacre to lethal effect. It was a surprising shift for the leading gun industry group, which in recent years has resolutely opposed any gun regulations. Immediately afterward the White House, too, said it was open to such a change.

The NRA announcement followed comments from leading congressional Republicans including House Speaker Paul Ryan that Congress should take a look at the devices, which were little-known even to gun enthusiasts prior to Sunday’s bloodbath. A gunman pumped bullets from a casino high-rise into a crowd of concertgoers below, killing 59 and wounding hundreds, apparently using legal “bump stocks” to increase firing speed from his semi-automatic weapons.

“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 said in a statement. “The NRA believes that devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations.”

White House spokeswoman Sarah Huckabee Sanders said in response, “We welcome that and a conversation on that. … It’s something we’re very open to. It’s something we want to be part of the conversation on going forward.”

President Donald Trump had discussed the issue with lawmakers on the way back from visiting Las Vegas on Wednesday, according to Rep. Mark Amodei, R-Nevada, who traveled with the president aboard Air Force One.