New York Attorney General Letitia James ordered 16 online companies to quit selling untraceable “ghost guns” on Monday.

The companies, which James did not identify for fear of directing them business, sell the parts needed to assemble assault rifles that are otherwise outlawed in New York, requiring just little finishing and assembly on the user’s part.

“Your website offers unfinished lower receivers that require simple milling in order to manufacture unregistered and un-serialized assault weapons, despite the fact that such manufacture and possession are illegal in New York,” James wrote in a letter sent to the targeted companies. “Nor does your website adequately warn New York consumers that using these products in the manner for which they are intended and advertised could result in imprisonment and/or fines.”

“The sale of such products to New Yorkers gravely endangers the public welfare by promoting the possession of illegal weapons and obstructing law enforcement investigations into the misuse of these weapons, and constitutes a criminal offense under New York State law,” she continued.

Merchants who defy the order could face a $5,000 penalty for each individual violation.

State lawmakers introduced legislation last week banning the practice, but the bill cannot be acted upon until the legislative starts in Jan. 2020.

Cuomo similarly signed a new law in July outlawing the manufacture and sale of 3D-printed guns, but the measure solely deals with the plastic printed firearms found to be untraceable by a metal detector.