Ukraine's weapons makers don't work in singular, large sites, and instead break manufacturing processes up across multiple locations.

AP Photo/Efrem Lukatsky

The Russian threat is real, and it's time for European defense companies to start copying Ukraine and break up production across multiple sites, a Ukrainian official and multiple defense firms told Business Insider.Russia's drone and missile attacks are so widespread that weapons companies working in Ukraine typically can't afford to work in large factories and warehouses that are more easily detected and struck. Factories in Ukraine, including those of US firms, have been hit. It has pushed many companies to split their sites up and go underground, though that makes their work producing weaponry harder and more expensive.Davyd Aloian, the deputy secretary of Ukraine's National Security and Defense Council, told Business Insider that the threat Russia poses to Europe is such that some allies need to start doing the same. "Some countries definitely should," he said.This is standard practice for many Ukrainian defense manufacturers. The CEO of Ukrainian-Estonian technology and defense company and ground drone maker Ark Robotics told Business Insider that his company had to do it despite the drawbacks, and it should become the norm for European defense manufacturing.The CEO, who asked to go by the pseudonym Achi out of concern for his safety, said his company's main strategy "is what we call distributed manufacturing: Breaking things up so that different components are made at different sites. It's necessary, but it's not ideal.""We try to avoid building a gigafactory. I would love that to be honest, I think this is literally the best way to do it. You build a huge factory, everything is in there."