Public Safety Canada says it's closely monitoring U.S. moves that would allow designs for 3D-printed guns to be posted online.

But it says in Canada a business licence is required to produce a firearm, regardless of how it's made.

It adds it's illegal to make or possess a firearm without the right licence and registration certificate.

Anyone who makes weapons or ammunition knowing they aren't authorized to do so could face up to 10 years in prison.

The legal wrangling in the U.S. around 3D-printed firearms dates back to 2013, when Texas-based Defence Distributed started publishing downloadable gun blueprints online.

The State Department ordered company founder Cody Wilson to cease, but the U.S. government settled with his company in late June, allowing the files to be posted again as of Wednesday.

Eight states have challenged the administration's move, arguing it threatens public safety.

U.S. President Donald Trump said on Twitter Tuesday he's looking into the matter, has spoken to the National Rifle Association and that it "doesn't seem to make much sense!"