South Korea said 600 North Korean troops were killed while fighting Ukraine.

South Korean lawmakers said Wednesday that about 600 North Korean troops fought against Russia and fought against Ukraine.

North Korea suffered about 4,700 casualties in the conflict, including deaths and injuries. However, some troops in the country have shown signs of improving combat capability over about six months by using modern weapons such as drones, such as drones.

"After six months of participating in the war, the North Korean military became less incompetent and its combat capability has been greatly improved because it was used to using new weapons, such as drones," a member of the parliamentary intelligence committee told reporters, who told reporters at the Korea National Intelligence Service.

A total of about 15,000 North Korean troops were deployed to fight Ukraine.

Putin thanks North Korea for sending troops to fight Ukraine: "Never forget heroism"

South Korean lawmakers say about 600 North Korean troops were killed, and Russia fought against Ukraine. (Sputnik/Kristina Corcholitsyna/Kremlin via Reuters)

Pyongyang agreed to deploy troops and provide weapons to Russia in exchange for technical assistance for spy satellites, drones and anti-air missiles, lawmakers said.

Earlier this week, North Korea confirmed for the first time that it had sent troops to fight Ukrainian forces. It claimed that it helped Russia regain Kursk territory controlled by Ukraine.

North Korea's Central Military Commission said on Monday that its leader Kim Jong-un had sent troops to Russia to "annihilate and eliminate Ukrainian neo-Nazi occupiers in Ukraine and cooperate with the Russian armed forces to liberate the Kursk region." The committee said North Korean forces ultimately made "important contributions" to Russia's occupation of border territory.

North Korea confirmed for the first time this week that it has sent troops to fight Ukrainian forces. (Getty Image)

Russian President Vladimir Putin thanked North Korea for sending troops and promised not to forget their sacrifices.

"The Russian people will never forget the heroism of the North Korean special forces," Putin said on Monday. "We will always respect the hero who sacrifices his life for Russia, for our common freedom, and fight alongside their Russian brothers."

Kremlin spokesman Dmitry Peskov said Russia could provide military assistance to North Korea if necessary under the Defense Treaty.

Trump blew Putin, questioning whether Russian leaders want peace or just "mocking me"

Russian President Vladimir Putin thanked North Korea for sending troops and promised not to forget their sacrifices. (Sputnik/Mikhail Metzel/Kremlin via Reuters/File Photo)

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In recent years, the two American opponents have been closer to each other.

Lee said the bodies of the dead North Korean soldiers were cremated in Kursk and then transported home.

North Korea is also believed to have sent about 15,000 workers to Russia and cited intelligence assessments, according to lawmakers.

U.S. President Donald Trump said on Saturday that he suspected Putin wanted to end the war. Just a day ago, Trump said Ukraine and Russia were "very close to the deal."

Reuters contributed to the report.