SAN FRANCISCO, Aug. 3 (Xinhua) -- The Attorney General (AG)'s Office of the U.S. west state of Washington said Friday that a hearing on a multistate lawsuit against 3D-printed guns has been scheduled for Aug. 21 in Seattle, the state's largest city.

"Preliminary injunction hearing in 3D-printed guns case set for 8/21," WA Attorney General@AGOWA tweeted, as 19 U.S. states including California, plus the District of Columbia, filed an amended complaint to block public sharing of online plans on 3D-printable weapons.

The Washington AG's Office said in a twitter post Thursday that the states of California, Colorado, Delaware, Hawaii, Illinois, Iowa, Minnesota, North Carolina, Rhode Island, Vermont and Virginia have joined the legal action.

Attorneys general from the states are asking the court to nullify an agreement between the U.S. State Department and Texas-based Defense Distributed to share online information on 3D-printable guns.

Defense Distributed, with its headquarters in Austin, Texas state, is an organization dedicated to global distribution of open-source, downloadable 3D-printed guns.

A court file said the data of downloadable guns for the automated production of firearms using a 3-D printer will make these weapons available to virtually anyone.

Plastic 3-D printed guns are functional weapons that are often unrecognizable by standard metal detectors and untraceable without serial numbers, it said.

The states said the settlement between U.S. President Donald Trump's administration undermines their ability to enforce gun laws, including background checks, and puts public safety at risk.

Washington AG Bob Ferguson announced on July 30 that he filed a lawsuit in the U.S. District Court for the Western District of Washington against the Trump administration.

"I am thankful and relieved Judge Lasnik put a nationwide stop to the Trump Administration's dangerous decision to allow downloadable, 3D-printed ghost guns to be distributed online," Ferguson said on July 31.

Ferguson's statement came in response to a temporary restraining order against the 3D-printed gun plans issued by Robert Lasnik, district judge of the U.S. District Court in Seattle.

Lasnik has blocked the Defense Distributed from posting instructions online for making 3D-printed firearms.

"These ghost guns are untraceable, virtually undetectable and, without today's victory, available to any felon, domestic abuser or terrorist. I hope the President does the right thing and directs his administration to change course," Ferguson said.