Ukraine’s drones range from small, autonomous boats patrolling the Black Sea to aircraft that travel hundreds of kilometres into Russia. Most are designed to be made from parts that are cheap, easy to find and simple to put together,

Drones operating via fiber-optic wires are a new military challenge globally, as they are largely immune to jamming and interception attempts.

Ukraine recently used inexpensive drones to inflict serious damage to Russia's strategic bomber fleet in an audacious attack.

The Ukrainian military says its new weapon system, which launches antiaircraft missiles from a remote-controlled speedboat, has brought down two Russian jet fighters.