Eighteen people have been killed and dozens injured in a wave of Russian strikes on cities across Ukraine, according to the Ukrainian government. The attacks involved dozens of Shahed attack drones, also known as 'kamikaze' drones, alongside missiles.
The Shahed-136, an Iranian-made drone also called the Geranium-2 by Russia, has explosives in a warhead on its nose and is designed to loiter over a target until instructed to attack. With a wingspan of about 2.5m, it can be hard to detect on radar. Defence experts estimate each drone costs about $20,000 (£17,800).
Ukraine's military reported that on 29 December, Russia used a total of 158 missiles and drones. Several drones struck the western city of Lviv, damaging residential buildings and a school. Ukraine says its air defences have managed to shoot down over 80% of all drones Russia has sent.
Both sides have increasingly used small, cheap commercial drones such as the DJI Mavic 3, which costs about £1,700. These are used for reconnaissance and guiding artillery fire, reducing the risk to troops.
