“For those North Korean soldiers who do not wish to return, there may be other options available,” Zelensky said on X. Those who want “to bring peace closer by spreading the truth about this war in Korean will be given that opportunity”, he added.

The Security Service of Ukraine (SBU) said one of the two soldiers told officials he thought he was going to Russia for “training”, rather than to fight.

He was found with a Russian military ID card issued in the name of another person. The other soldier had no documents.

SBU said the two men, who were taken prisoner on 9 Jan, are in Kyiv and receiving medical care.

They only speak Korean and are being questioned with the assistance of South Korea’s National Intelligence Service, SBU said.

Russia has not denied using North Korean troops in its war against Ukraine. President Vladimir Putin said in October that it was his country’s “sovereign decision” whether or not to deploy such troops.

On Saturday, Zelensky posted photographs of the two captured soldiers, showing one of them with his head and chin in bandage, while the other had both his hands fully wrapped up.

Zelensky also shared a photo of a red Russian military ID card that gives the place of birth as Turan, in the Russian republic of Tuva, which shares a border with Mongolia.

SBU said that the soldier found with the ID card told interrogators he had been issued the document during the autumn of 2024, in Russia.

According to SBU, he also said that some of North Korea’s combat units had undergone a one-week training at the time.

“It is noteworthy that the prisoner…emphasises that he was allegedly going for training, not to fight a war against Ukraine,” the SBU statement said.

Zelensky’s office said in a statement on Saturday that the Russians “are trying to hide the fact that these are soldiers from North Korea by giving them documents claiming they are from Tuva or other territories under Moscow’s control”.

The intelligence service reported that the soldier carrying the ID card said he was born in 2005 and had been serving North Korea as a rifleman since 2021.

The second prisoner is reported to have given some of his answers in writing because he had an injured jaw, according to SBU.

SBU said it believed he was born in 1999 and had been serving North Korea as a scout sniper since 2016.

The Geneva Conventions state that the questioning of prisoners should be carried out in a language they understand and prisoners must be protected against public curiosity.

BBC News and other international media have not yet verified Ukraine’s account of the prisoners and their capture.

Ukraine and South Korea reported late last year that North Korea had sent at least 10,000 troops to Russia.

South Korea’s National Intelligence Service said on Monday that more than 300 North Korean soldiers have died while fighting for Russia, and at least 2,700 of them have been wounded.

In December, South Korea’s intelligence agency reported that a North Korean soldier believed to have been the first to be captured while supporting Russia’s war in Ukraine had died after being taken alive by Ukrainian forces.

Zelensky said on Sunday “there should be no doubt left that the Russian army is dependent on military assistance from North Korea”.