Gun shops in the United States are reportedly selling out of a gun accessory known as a bump stock in the wake of the Las Vegas mass shooting.
The device transforms a semi-automatic rifle into a weapon which can fire hundreds of rounds a minute and was used by gunman Stephen Paddock when he killed 58 people in the deadliest mass shooting in modern US history.
Authorities say he had 12 rifles outfitted with bump stocks among the arsenal of weapons in his hotel room, and audio of the attack suggested he used weapons with rapid-fire capabilities.
Democratic US Senator Dianne Feinstein introduced a bill on Wednesday that would outlaw bump stocks and other devices that, as she put it, "easily and cheaply modify legal weapons into what are essentially machine guns".
Several Republicans, who typically oppose gun restrictions, signalled they were open to the idea.
Republican Representative Carlos Curbelo was also preparing a measure to ban the ownership, manufacture and transport of the devices. He said there was growing bipartisan consensus, but cautioned against assuming that a legislative win was certain.
Republican House Speaker Paul Ryan told a US radio programme he was open to regulating the devices.
"Clearly that's something we need to look into," Mr Ryan said, adding that many lawmakers had not been aware until now that such devices existed.
"I didn't even know what they were until this week," he said. "I think we're quickly coming up to speed with what this is."
The National Rifle Association - the influential pro-gun lobby group - said bump stocks should be "subject to additional regulations" and called on regulators to determine whether the devices comply with federal law.
According to several gun dealers, the device is more of a novelty item than a popular seller, in part because it sacrifices accuracy and uses so much costly ammunition.
For more than a year, the Georgia Gun Store in Gainesville, Georgia, had had no requests for the attachment, but after the Las Vegas shooting, it fielded several calls from customers asking about the product, apparently out of concern that lawmakers may outlaw it.
The store's owner, Kellie Weeks, said several distributors were out of stock when she called them seeking supplies.
"Anybody that wants to get them is probably just worried that they're going to be banned," Weeks said.
Slide Fire, a leading manufacturer, has reportedly sold out of the device, while many gun shop owners say they are fielding dozens of calls about the devices, over fears they may be banned.
The increased interest in bump stocks echoed the spike in gun sales that often follows a high-profile mass shooting, as gun owners become concerned about stiffer gun control laws. Gun company stocks rose in market trading following Sunday's attack.
In a probable effort to avoid controversy, Wal-Mart Stores Inc and sporting goods store Cabela's both appeared to pull bump stocks from their websites on Wednesday. Calls to the companies seeking comment were not returned.
On Wednesday, comments on the Facebook page for Slide Fire were split between critics who blamed the company for the massacre and customers who said they planned to buy more bump stocks. The owner of Slide Fire, Jeremiah Cottle, did not respond to numerous messages seeking comment.
C.J. Calesa, an employee at Birmingham Pistol Wholesale in Trustville, Alabama, said the store began receiving calls from customers about bump stocks on Tuesday.
"They do sell a little bit, but it's very minimal," he said.
"We usually sell 10 or so a year. I have no idea why, but anytime an unfortunate situation happens and they start talking about getting rid of stuff, we get those phone calls," he said.