The US State Department has that demanded designs for a 3D-printed gun be removed from the internet.
But the order to remove the blueprints for the plastic gun comes after over 100,000 people have downloaded them since they were uploaded a week ago.
The US Government has suggested to the gun's manufacturer, Defense Distributed, that publishing the plans online may breach arms control regulations.
The blueprints have now been removed from the company's Defcad site, but it is not clear whether this will stop people accessing them: they many still be present on servers belonging to the site's hosting company, and many links to copies of the plans have been uploaded to file-sharing site The Pirate Bay, which has publicised their existence via Reddit.
Defense Distributed's founder Cody Wilson describes himself as a 'crypto-anarchist', claiming it is the right of everybody to own a gun.
The Office of Defense Trade Controls Compliance wrote to Mr Wilson demanding the designs be "removed from public access" until he could prove he had not broken laws governing shipping weapons overseas by putting the files online and letting people outside the US download them. In an interview by Forbes magazine, he commented "We have to comply," adding that the State Department's fears were ungrounded, as his company had been set up specifically to meet requirements that exempted it from the arms control regulations. He said that he welcomed the government's intervention as it would highlight the issue of whether it was possible to stop the spread of 3D-printed weapons.
3D printing is a process of making a three-dimensional solid object of virtually any shape, from a digital model. It uses an additive process, laying down successive layers of liquid resin or other material which are then cured into the shapes required, distinct from traditional milling. It is used widely in prototyping, limited-run manufacturing and increasingly in dentistry and prosthetics.
Defense Distributed's gun is made from high density plastic that could withstand and channel the explosive force needed to fire a bullet. Its first firing made news headlines worldwide and has been the subject of hundreds of thousands of YouTube downloads.