What military drones do Ukraine and Russia have?
Ukraine's main military drone is the Turkish-made Bayraktar TB2. It is about the size of a small plane, has cameras on board, and can be armed with laser-guided bombs.
Ukraine started the war with a fleet of "fewer than 50" of these, says Dr Jack Watling of think tank the Royal United Services Institute (Rusi).
Russia mainly uses the "smaller, more basic" Orlan-10, he says. "Russia started the war with some thousands of them, and may have a few hundred left." These drones also have cameras and can carry small bombs.