The Biden administration will announce new regulations to limit the spread of "ghost guns" as soon as Monday, according to reports.
Inside sources told the Associated Press that the Justice Department is preparing to reveal its long-awaited new rules on untraceable homemade firearms.
Ghost guns are so called because they lack serial numbers and can therefore circumvent background checks and gun licence laws.
In recent years home ghost gun kits have become widely available online, with the critical components required for them to legally count as a firearm sold separately or 3D printed at home.
That has led to ghost guns being used in numerous murders and crimes, including a mass shooter who had been banned from owning firearms and a teenager who fatally shot two classmates.
According to the Justice Department, nearly 24,000 ghost guns found at crime scenes were reported to the federal government between 2016 and 2020. Untold numbers of other guns were never reported because local law enforcement agents could not trace them.
However, any new action is likely to face resistance after Mr Biden was forced to withdraw his nomination of a gun control advocate to lead the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) in the face of resistance from Republicans in Congress.
On Sunday Senate Democratic leader Chuck Schumer urged Joe Biden's government to act soon, saying: "It's high time for a ghost gun exorcism before the proliferation peaks, and before more people get hurt – or worse.
"My message is a simple one: no more waiting on these proposed federal rules.... these guns are too easy to build, too hard to trace, and too dangerous to be allowed."
The Justice Department is expected to change the federal legal definition of a firearm to include unfinished parts, such as the "80 per cent complete" receivers that are often sold as the final component of a home ghost gun kit.
Last year, the ATF proposed to require those who make and sell ghost gun parts to be licensed by the federal government, add serial numbers to their products, and run background checks on some customers.