ICE general manager Karl-Magnus Troedsson confirmed to PC Gamer at E3 that Battlefield 4 will not support mods. Troedsson caveated that user-generated content is something that DICE finds very interesting, and that its something the studio has been talking about at a high level.

PCG: Is there any chance of Battlefield 4 being moddable? 

Karl-Magnus Troedsson, DICE GM: We get that question a lot. I always answer the same thing, and then the community calls me bad names. We get the feedback, we understand it. We also would like to see more player-created content, but we would never do something like this if we feel we couldnt do this 100 percent. That means we need to have the right tools available, we need to have the right security around this regarding what parts of the engine we let loose, so to say. So for BF4 we dont have any planned mod support, I have to be blunt about saying that. We dont.

DICE: No mods for Battlefield 4