CHICAGO • A United States judge temporarily blocked the online publication of blueprints for 3D-printed firearms, in a last-ditch effort to stop a settlement President Donald Trump's administration had reached with a company releasing the digital documents.
Eight states and the District of Columbia, which houses the capital Washington, had filed a lawsuit against the federal government, calling its settlement with Texas-based Defence Distributed "arbitrary and capricious".
The Trump administration had settled a five-year legal fight by permitting the company to publish its website Defcad - which founder Cody Wilson envisioned as a WikiLeaks for home-made firearms called "ghost guns".
Those weapons can be manufactured using 3D printers or personal steel mills, and lack traceable serial numbers. At least one of the guns can also be made from plastic, which is virtually invisible to metal detectors.
US District Judge Robert Lasnik in Seattle, Washington, granted on Tuesday the plaintiffs' motion for a temporary restraining order blocking the release of the digital plans, and scheduled a hearing for Aug 10.
In a written statement, New York Attorney-General Barbara Underwood, one of the plaintiffs, called the ruling "a major victory for common sense and public safety".
"It is - simply - crazy to give criminals the tools to build untraceable, undetectable 3D-printed guns at the touch of a button. Yet that's exactly what the Trump administration decided to allow."
Mr Trump expressed scepticism over the legality of Mr Wilson's efforts, even though his administration had green-lighted the project.
"I am looking into 3-D Plastic Guns being sold to the public," the President said on Twitter, revealing that he had spoken to America's main pro-gun lobby, the National Rifle Association (NRA).
"Already spoke to NRA, doesn't seem to make much sense!"
White House spokesman Hogan Gidley told reporters on Tuesday: "It is currently illegal to own or make a wholly plastic gun of any kind - including those made on a 3D printer.
"The administration supports this nearly two-decade-old law."
Twenty-three Democratic senators later introduced a Bill designed to block the publication of 3D-printable firearm blueprints.
Mr Wilson remained defiant and vowed to fight in court. "Americans have the unquestionable right to share this information," he told Wired magazine.
The self-proclaimed "crypto-anarchist" also made the digital blueprints available online on Tuesday, a day earlier than the launch date he had previously announced.
Agence France-Presse was able to download two files from the website, which had 10 firearms and weapons components with downloadable digital files.
Mr Wilson, a law school dropout, contends that the US Constitution's Second Amendment, which guarantees the right to bear arms, should extend to a person's right to make their own guns.
Before the settlement with the Trump administration, Mr Wilson had lost in both district and appellate courts.
The US Supreme Court had declined to take up his case.
But the phenomenon of "ghost guns" is bigger than his website alone. Last month, Los Angeles police showcased an arsenal of such weapons seized from gang members.