Russian arms depot on fire after Ukraine launches more than 100 drones

Recently built fortifications are seen in Donetsk region, Ukraine (Alex Babenko/AP)

A blaze has torn through an arms depot deep inside Russia, triggering explosions and the closure of a major highway, after Ukraine launched more than 100 drones overnight.

The depot appeared to be close to another that was struck by Ukrainian drones early on Wednesday, injuring 13 people and also causing a huge fire.