South Korea’s Foreign Ministry said Sunday it was trying to verify a statement from Russian authorities claiming that four Koreans who joined as volunteer fighters in Ukraine have died.

The Moscow Times, an independent English-language and Russian-language online newspaper, released a report quoting a statement from Russia’s Defense Ministry on Friday that claimed 1,956 “mercenaries and weapons specialists” had been killed among the 6,956 from 64 countries who had arrived in Ukraine since the start of the war. Another 1,779 have left Ukraine, the statement claimed.

Since the war broke out in February, 13 South Koreans have entered Ukraine as volunteer fighters, according to the Russian ministry. Of them, four have been killed and eight have left the country, it claimed, while one remains in Ukraine.

“We are aware of what Russia’s Defense Ministry said. We have ordered the Korean Embassy in Russia to verify the claim,” a Foreign Ministry official said in a press statement.

According to the Russian ministry’s statement, Poland was the “absolute leader” among European countries in terms of number of volunteer fighters joining Ukraine’s side, followed by Romania and Britain.

Among the 1,831 Poles who joined as the volunteer fighters for Ukraine, 378 have died and 272 have returned home, the Russian ministry said.

Some hundreds of volunteer fighters from Romania, Canada and the United States also entered Ukraine.

The Russian ministry also explained that the number of foreign fighters was decreasing, and many are leaving Ukraine due to a “growing number of military failures of the Kyiv regime and massive daily losses in manpower and equipment.”

Among South Korean returnees is Rhee Keun, a Navy SEAL-turned-YouTuber who arrived at Incheon Airport on May 27 after getting injured. He returned to Korea about three months after he left for Ukraine.

Before Rhee’s return to Korea, Ukraine’s International Legion of Territorial Defense said in a tweet that Rhee “sustained injuries on the battlefield” and that he “will return home for rehabilitation,” calling him by his English name, Ken.

As South Korea bans its nationals from traveling to war-stricken countries, the prosecution is currently investigating Rhee for his involvement in the war.

By Jo He-rim (herim@heraldcorp.com)