Ukraine’s President Volodymyr Zelensky said Wednesday that Ukrainian intelligence had identified 155 Chinese citizens fighting alongside Russian forces, a day after Ukraine said two Chinese nationals were captured in the country.

Axar.az reports, citing CNN, the Chinese nationals had been recruited through advertisements, including on social media, Zelensky said in a briefing Wednesday.

“We are collecting information and we believe that there are more, many more,” Zelensky said Wednesday, before claiming that Beijing was aware of Russians placing recruitment videos on Chinese social networks.

“These people arrive to the Russian Federation, to Moscow. Medical examinations last three to four days. Training centers are for one to two months. They fight on the territory of Ukraine,” he added.

Asked whether he thought the presence of Chinese nationals in Ukraine was a result of official Beijing policy, Zelensky said: “I don’t have an answer to this question yet. The Security Service of Ukraine will work on it … We are not saying that someone gave any command, we do not have such information.”

China has consistently denied any involvement in the war.

A spokesperson for China’s Ministry of Foreign Affairs said earlier Wednesday that any claims that Chinese citizens are fighting in Ukraine were “groundless.”

“It is important to emphasize that the Chinese government has always instructed its citizens to stay away from areas of armed conflict and avoid getting involved in the conflict in any form, especially avoiding participation in any party’s military operations,” spokesperson Lin Jian said in a press conference.