April 10 (UPI) — Ukrainian President Volodymyr Zelensky said his intelligence services had documentary evidence that at least 155 Chinese nationals were fighting on the Russian side in its war on Ukraine.

“There are 155 Chinese citizens who are fighting against Ukrainians on the territory of Ukraine,” President Volodymyr Zelensky told reporters at a news briefing Wednesday night.

“We are collecting information, we believe that there are many more. For these 155, we have passport data, where they are from, their Chinese documents, age, etc. Also units where they’re serving, 70th, 71st, 255th motorized rifle regiments and others,” he said.

“After recruitment, these people arrive in Moscow, where they undergo 3-4 days of medical examinations and 1-2 months in training centers. They fight on the territory of Ukraine. They receive migration cards, as well as a card of the Mir payment system [Russia’s equivalent of the Visa or Mastercard payment networks], for which they receive money, respectively.”

The men had been recruited through a Russian advertising campaign rolled out over Chinese social networking channels and more mainstream social media, including TikTok, which is Chinese-owned, using promotional videos, according to Zelensky.

He added that “official Beijing” was aware of what was going on but suggested clandestine recruitment may also be happening alongside.

The claims came a day after Ukraine said it had captured two Chinese citizens fighting for Russia in Ukraine’s eastern Donbas region, one of the frontlines in the war.

Ukraine Foreign Minister Andrii Sybiha summoned China’s charge d’affaires to get answers, warning the discovery called into question China’s claim to support peace and undermined its credibility as a “responsible” permanent member of the U.N. Security Council.

China’s Foreign Ministry said it was working to verify the reported involvement of Chinese citizens in the war with Ukrainian officials but rejected the claim there were many more than the two that had been captured.

“Such claim has no basis in fact. Let me stress that the Chinese government always asks Chinese nationals to stay away from areas of armed conflict, avoid any form of involvement in armed conflict, and in particular avoid participation in any party’s military operations,” said spokesman Lin Jian at his regular briefing Wednesday.

He said Ukraine needed to “correctly view” the clearly constructive role China was playing in working toward a political settlement of the Ukraine conflict, insisting its positive stance was widely recognized by the rest of the international community.

Lin said he had no information on whether Ukraine had previously raised the issue with Beijing through formal channels.

Ukraine’s Pravda news website reported that one of the Chinese men had told his Ukrainian captors that he had paid $3,530 to an intermediary to enlist in Russian forces as a route to Russian citizenship and that he trained among a group of other Chinese in Russian-occupied Luhansk, which together with Donetsk makes up the Donbas region.

The prisoner said some of his countrymen in the group were escaping “legal issues” back home in China and that he had traveled to Russia as a “tourist.”

North Koreans have also become involved in the conflict, with some 11,000 believed to be fighting Ukrainian forces in Russia’s Kursk province after Kyiv invaded part of the region in a counteroffensive in August.