Federal Judge Robert Lasnik issued a temporary restraining order on Tuesday "blocking federal government from allowing distribution of downloadable 3D printed" guns, according to a tweet from the Washington State Office of the Attorney General.
"The judge's rule is clear," Washington Attorney General Bob Ferguson said at a news conference. "We go back to the status quo, before the federal government made the disastrous decision to undo these protections for public safety."
At least 10 US states were scrambling to block access to plans that would allow people to print 3D guns on Tuesday.
New York Gov. Andrew Cuomo announced a series of actions Tuesday to prevent the distribution of the 3D gun designs. Cuomo issued a cease-and-desist letter to Defense Distributed, a Texas gun-rights organization that posts the plans online, to block the distribution of designs for 3D guns in New York. The governor called the impending release "reckless."
Cuomo also directed state police to issue a notice reminding New Yorkers that manufacturing firearms defined as assault weapons is illegal in New York.
"As the nation rises up and calls for action against gun violence, it is absurd and frightening that the federal government wants to make accessing an automatic weapon as easy as hitting print," he said. "New York is proud to have the strongest gun safety laws in the nation, and we won't let this federal government take us backwards."
Cuomo said he will pursue legislation to bolster the state's gun safety laws and outlaw private production of all 3D and so-called "ghost guns" that are untraceable and invisible to metal detectors.
Cuomo's actions came after Pennsylvania went to court Sunday to block early distribution of the plans, which weren't supposed to be available for download until Wednesday. But more than 1,000 designs were downloaded recently, in advance of the agreed upon August 1 date.
At the hearing, Defense Distributed agreed to block Pennsylvania IP addresses for a few days until a more formal hearing could be held.
Josh Blackman, a lawyer for Defense Distributed, told CNN on Monday the Pennsylvania case was about free speech rights, not the manufacture of guns.
"One state cannot censor the speech of a citizen in another state," he said.
Other states also are trying to bar access to 3D printed guns. Iowa and Virginia on Tuesday announced they are joining a federal lawsuit that asks a judge to block the court action that lets people download plans
These latest battles flared after Defense Distributed reached a settlement in June with the federal government that will allow it to post 3D printable gun plans online.
The settlement ended a multiyear legal battle that started when Defense Distributed founder Cody Wilson posted designs for a 3D printed handgun he called "The Liberator" in 2013. The single-shot pistol was made almost entirely out of ABS plastic -- the same material Lego bricks are made from -- and could be made on a 3D printer.
Wilson sued the federal government in 2015.
NRA says plastic guns are illegal
The National Rifle Association said Tuesday that undetectable guns are illegal.
"Many antigun politicians and members of the media have wrongly claimed that 3D printing technology will allow for the production and widespread proliferation of undetectable plastic firearms," said Chris Cox, the NRA's executive director for legislative action.
"Regardless of what a person may be able to publish on the internet, undetectable plastic guns have been illegal for 30 years. Federal law passed in 1988, crafted with the NRA's support, makes it unlawful to manufacture, import, sell, ship, deliver, possess, transfer, or receive an undetectable firearm."
Cox was referring to the Undetectable Firearms Act of 1988.
The statement came hours after President Donald Trump expressed skepticism over the ability to legally download plans for 3D printed guns, saying in a tweet that he's spoken with the NRA about them because the technology "doesn't seem to make much sense!"