A thousand North Korean troops who have been fighting in the Kursk region of Russia have been killed in Vladimir Putin ’s war with Ukraine, officials have said. Western officials have told the BBC that 36 per cent of North Korean forces fighting in Russia had been killed, injured or captured by mid-January.

The officials, who spoke on grounds of anonymity, said that out of the estimated 11,000 troops sent from North Korea, known as DPRK (Democratic People's Republic of Korea), 4,000 were battle casualties.

Ukraine's military said 21 troops were killed and 40 injured in the operation in the Russian region where it is staging an incursion.