A senior Ukrainian defense official has expressed his view that North Korean troops fighting alongside Russian forces have fully mastered modern fighting tactics, posing a serious threat on the battlefield.

Andrii Cherniak, a spokesperson of the Main Intelligence Directorate of Ukraine's Defense Ministry, spoke to NHK on Thursday about North Korean troops that have been deployed to the western Russian region of Kursk.

Ukrainian forces have been engaging in cross-border attacks on the region.

Cherniak said North Korean casualties have so far amounted to around 5,000, and 6,000 other soldiers from the country are in Kursk and can continue to fight.

He noted that North Korean troops initially went on some kind of large-scale offensive and were immediately defeated by Ukrainian artillery and drones.

He said this has made them change their tactics, and they are now moving in groups of one to two people.

Cherniak said, "Unfortunately, we can talk about the evolution, about the successful training of the North Korean military."

He said the North Korean soldiers have learned the tactics of using unmanned aerial vehicles and electronic warfare. He added that they are fully mastering the weapons and tactics which Russia uses on the battlefield.

Cherniak also noted it was considered that there would be a language barrier between North Korean and Russian forces.

But he expressed his view that the troops from North Korea have been fulfilling their duties as assault units, even without communicating with the Russian military.

Specifically, he said North Korean soldiers receive some commands or instructions to "reach this or that frontier" and then go forward. He added that once they have completed their task, they get a foothold there without constant communications with the Russian side.

He also pointed out that Russia's military is considering attacks on Sumy in northeastern Ukraine and the eastern region of Kharkiv.

He did not rule out the possibility that North Korean soldiers will be involved in these offensives.

Cherniak also noted that half of the shells used by Russia are made in North Korea, which he said is also supplying missiles to Russia.

He said that these missiles were at first not so accurate and they would land more than 100 meters away from their intended targets, but they have now become much closer to targets.

Cherniak said North Korean troops in Kursk will take the tactics of modern warfare back home and teach them to other soldiers in their country.

He said North Korea is a threat to Ukraine and the Asia-Pacific region.