The first strike, against an ammunition depot, comes days after the U.S. authorized the use of ATACMS on Russian territory.

Ukraine has been pleading with the US for months to let it use American-made weapons to hit military targets inside Russia beyond the border zone. Now, as he nears the end of his presidency, Joe Biden has relented and decided to lift some restrictions,

Ukrainian troops have launched an attack against a Russian border region with six US long-range missiles, Moscow has said. It comes after Vladimir Putin approved an updated doctrine lowering the threshold for the use of nuclear weapons.