WASHINGTON (AP) -- An Army unit based in Europe that was specializing in drone warfare has been directed to end its efforts to learn and use the battlefield technology and return to being a traditional infantry battalion, officials said Thursday. For more nearly a year, soldiers of the 173rd Airborne Brigade have been experimenting and building their own drones, as well as participating in drills on waging unmanned warfare after Ukraine pioneered such tactics in its yearslong conflict with Russia. Last November, 600 soldiers formed a battalion that specialized in drone warfare and was set up to be used as a dedicated unit that could deploy anywhere drones were required.