Germany has given Ukraine the green light to strike targets inside Russia using long-range weapons supplied by Berlin, in a decision that signals a notable hardening of Western resolve as the war grinds on.

A Ukrainian drone attack last weekend likely damaged around 10% of Russia's strategic bomber fleet and hit some of the aircraft as they were being prepared for strikes on Ukraine, a senior German military official said.

Most of the drones and missiles were intercepted, according to the Ukrainian Air Force, and there were no immediate reports of widespread damage.