Vehicles used in drone warfare include unmanned combat aerial vehicles, uncrewed surface vessels, [1] unmanned ground vehicles, [2] unmanned underwater vehicles, [3] and space drones. [4] Drones are increasingly used in war. [5] Some drones are used by both civilians and military. [6] The difference between military robots and military drones is unclear as of 2025: some say that lethal autonomous weapons are robots whereas others describe “fully autonomous military drones”. [7] Artificial intelligence is not widely used in military drones as of 2025, but is being tested. [8] Whether military drones can drill underground is unknown as of 2025. [9] Drones may be commanded by a separate branch of the armed forces, such as Unmanned Systems Forces. Military drones are regulated by international law. [7]