Officials have suggested permission for wider use could be response to North Koreans joining war on Putin’s side

Joe Biden has lifted the ban on Ukraine using long-range missiles to fire into Russian territory by permitting them to be used against Russian and North Korean forces in the Kursk region.

The president has allowed Ukraine to use US-made Atacms rockets, which have a range of 190 miles (300km) – the first time the outgoing president has given Kyiv permission to any use long-range weapons inside Russia.