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

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.

That term comprises those killed, wounded, missing or captured. Of the 4,000, the officials said around 1,000 are believed to have been killed by mid-January.

These losses, if confirmed, are unsustainable by the North Koreans.

It is not clear where the wounded are being treated, nor even when and to what extent they will be replaced.

But the figures point to an extraordinarily high cost being incurred by President Vladimir Putin's ally, akin Kim Jong Un, as he seeks to help him evict Ukrainian forces from Russia ahead of any possible ceasefire negotiations later in the year.

Ukraine launched a lightning thrust into the Russian oblast of Kursk last August, taking Russian border guards by surprise.

The government in Kyiv made it clear at the time that it had no intention of holding onto the territory seized, merely to use it as a bargaining chip in future peace negotiations.

Ukraine's early gains in Kursk have since been steadily pushed back, partly due to the arrival in Russia of the North Koreans in October.

But Ukraine still retains several hundred square kilometres of Russian territory and is inflicting huge losses on its enemy.

The North Korean troops, reportedly from an "elite" unit called the Storm Corps, appear to have been thrown into the fight with comparatively little training or protection.

"These are barely trained troops led by Russian officers who they don't understand," says the former British Army tank commander, Col Hamish de Bretton-Gordon.

"Quite frankly they don't stand a chance. They are being thrown into the meat grinder with little chance of survival. They are cannon fodder, and the Russian officers care even less for them than they do for their own men."

Reports attributed to South Korean intelligence say the North Koreans are unprepared for the realities of modern warfare, and appear especially vulnerable to being targeted by Ukrainian First-Person-View (FPV) drones, a weapon that has been a familiar part of the battle space further south in Ukraine's Donbas region for years now.

Despite this, Ukraine's top military commander Gen Oleksandr Syrskyi warned earlier this week that North Korean soldiers were posing a significant problem for Ukrainian fighters on the front line.

"They are numerous. An additional 11,000-12,000 highly motivated and well-prepared soldiers who are conducting offensive actions. They operate based on Soviet tactics. They act in platoons, companies. They rely on their numbers," the general told Ukraine's TSN Tyzhden news programme. (BBC)

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