Police in Britain say they seized a 3D printer and suspected printed components for a gun, believed to be first-ever seizure of such a next-generation weapon.

The alleged plastic gun parts and the 3D printer were discovered, along with a quantity of gunpowder, when officers executed warrants in Manchester Thursday as part of the largest ever multi-agency operation to target organized crime in the city, The Guardian reported.

Police called it a "really significant discovery" of the next generation of firearms that criminals could conceivable make in the privacy of their homes and smuggle with ease because they could avoid X-ray detection with their plastic construction.

"If what we have seized is proven to be viable components capable of constructing a genuine firearm, then it demonstrates that organized crime groups are acquiring technology that can be bought on the high street to produce the next generation of weapons," Manchester Detective Inspector Chris Mossop said.

A man has been arrested on suspicion of making gunpowder and was being held for questioning, police said.