China’s foreign ministry on Wednesday rejected accusations by Ukraine that more Chinese citizens were fighting there on behalf of Russia, calling the assertion “groundless.”

President Volodymyr Zelensky of Ukraine had said a day earlier, without providing evidence, that two Chinese men fighting alongside Russian troops had been captured and that there were “many more” on the battlefield. The Trump administration, which has escalated a trade war against China, called the news “disturbing.”

On Wednesday, a spokesman for China’s foreign ministry, Lin Jian, said that Beijing was “verifying the relevant situation” about the two men with Ukraine. He dismissed the suggestion that many more Chinese citizens were fighting for Russia and stressed that Beijing instructed its citizens to avoid any involvement in armed conflicts.

“China’s position in the Ukraine crisis is very clear and is widely recognized by the international community,” Mr. Lin told a news briefing.

The back-and-forth comes at a tense time for both Ukraine and China. The Trump administration has drawn closer to Moscow while trying to act as a mediator in cease-fire talks with Kyiv, and it has also taken aim at Beijing, with a sharp escalation of threats and a 104 percent tariff on all Chinese goods that went into effect on Wednesday.

The State Department spokeswoman, Tammy Bruce, on Tuesday called the report of Chinese citizens fighting for Russia as “disturbing.”