Gun control advocates are trying to stop an Austin-based nonprofit from posting gun schematics for 3-D printers online.

Three of the country's largest gun-violence prevention groups filed a motion in a Texas federal court Thursday asking a judge to intervene and block Defense Distributed from being able to publish the files.

Cody Wilson got the green light to publish files for 3-D printed guns in the form of a settlement agreement with the U.S. government earlier this month.

He’d sued the Department of State after he was ordered in 2013 to take down files he’d put online that could be downloaded and used to print guns.

The settlement agreement gave Wilson’s nonprofit, Defense Distributed, government permission to distribute such files — which has gun-safety advocacy groups worried.

“For years — years — our federal government thought that having foreign actors being able to access these blueprints would endanger public safety,” said Avery Gardiner, co-president of the Brady Center to Prevent Gun Violence, one of the groups behind the joint motion. “It seems to have changed its mind on that without any explanation.”

Cody Wilson with a 3-D printed gun. (Lorenza Baroncelli / Defense Distributed)

The settlement says people can legally download plans to print firearms at home. Becca DeFelice, who heads the San Antonio chapter of Moms Demand Access for Gun Sense in America, fears that the technology could allow guns in the hands of dangerous people.

“It's not just gun-violence prevention groups who oppose this — any responsible Texan will have an objection to this,” DeFelice said. “It really flies in the face of common sense.”

The 3-D printed guns could be a way to circumvent laws requiring background checks for gun ownership, advocates fear. When the settlement was announced July 10, Wilson tweeted a gravestone engraved that read “AMERICAN GUN CONTROL.”

A closed emergency hearing was called in Austin after the groups — the Brady Center, Everytown for Gun Safety and Giffords Law Center to Prevent Gun Violence — filed their motion just after midnight Thursday, a spokesman for the Brady Center said. Another hearing is set for 2 p.m. Friday.

Also Thursday, the New Jersey attorney general sent Defense Distributed a cease-and-desist letter demanding that Wilson "halt publication of the printable-gun computer files," or the office will initiate legal action.