Western officials have told the BBC that North Korean troops have already suffered nearly 40% casualties in the fighting in Russia's western Kursk region, in just three months.

North Korea will send reinforcements to join its troops fighting alongside Russia against Ukraine in the next two months, The New York Times reported on Wednesday, citing a senior U.S. Department of Defense official.

North Korea had sent 11,000 soldiers to assist Russia, many of whom were killed. The Pentagon expects a new batch to arrive at the front, The New York Times reports, citing a senior US Department of Defense official.

Ukrainian forces described a different kind of enemy, fighting with unfamiliar tactics and little option to retreat.

It will mostly be missile and artillery troops who typically operate hundreds of tubed and rocket artillery systems as well as the KN-23 short-range ballistic missiles Pyongyang has already provided Moscow,

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.

There is mounting evidence from the battlefield, intelligence reports and testimonies of defectors that some North Korean soldiers are resorting to extreme measures as they support Russia's three-year war with Ukraine.

"I didn't even know who we were fighting against," the captured soldier from Pyongyang told Ukraine's Security Service.