Seoul, Dec 16 (IANS): Some 200 Russian and North Korean soldiers were estimated to have been killed while fighting in combined units against Ukrainian forces, Kyiv's intelligence authorities said, without specifying the number of casualties for each side.

The Defence Intelligence of Ukraine (DIU) made the revelation in a statement, noting that North Korean soldiers have been mobilised for assault operations as part of combined units of Russia's Marine Corps and airborne troops, Yonhap news agency reported on Monday.

Claiming that the North Korean troops suffered 'irreversible losses' from Ukraine's attacks, the DIU said the language barrier is an issue for Russian and North Korean combined units in conducting coordinated operations.

"Because of this problem, North Korean soldiers opened 'friendly fire' on the vehicles of the so-called Ahmat battalion. As a result, they killed eight Kadyrov soldiers," it said," referring to Chechen fighters.

The Ukrainian military also released photos and footage of what appear to be dozens of North Korean soldiers killed along with Russian troops in Russia's Kursk border region, according to a Ukrainian media outlet.

Ukrainska Pravda reported on Sunday, citing information from a drone unit, that the soldiers whose bodies were shown covered in snow were killed during assaults in the Russian region bordering Ukraine on Saturday (local time).

"The Madiar channel emphasised that this is a collaborative effort of FPV (first person view)-drone pilots of the 414th Unmanned Strike Aviation Systems Regiment, the Mahura Brigade, the 95th Air Assault Brigade, the 36th Separate Marine Brigade, the 1st Tank Brigade and the 17th Tank Brigade," the outlet said.

The details of the post shared on the drone unit's Telegram channel could not be verified immediately.

On Saturday, Ukrainian President Volodymyr Zelenskyy said Russia could extend its deployment of North Koreans to other parts of the front line.

"We already have preliminary data that the Russians have begun to use North Korean soldiers in their assaults. A significant number of them," Zelenskyy said in an address.

"The Russians include them in combined units and use them in operations in the Kursk region. So far, only there. But we have information suggesting their use could extend to other parts of the front line," he said.

South Korea and the United States have accused North Korea of sending thousands of soldiers to Russia, with some of them engaging in combat in the western Kursk border region.