KYIV, Ukraine >> The Ukrainian military has captured two Chinese men fighting alongside the Russian army in the eastern Donetsk region and has information that “significantly more” are with Russian forces, Ukraine’s President Volodymyr Zelenskyy announced on Tuesday.

There was no immediate comment from China. Beijing is not known to have provided Russia with weapons or military expertise, and it was not clear whether the Chinese had joined the fight on their own initiative. Russia allows foreigners to enlist in its military, as does Ukraine.

Zelenskyy said he asked his top diplomat “to immediately contact Beijing.” He said China would be the third country to offer military support to Russia after Iran, which has supplied attack drones, and North Korea, which has supplied soldiers, according to American and South Korean officials.

China has provided strong diplomatic support for Russia since Moscow launched its full-scale invasion of its neighbor in February 2022. Beijing has also offered an economic lifeline through the trade in energy and consumer goods.

Zelenskyy said a clash with Chinese soldiers occurred near the villages of Tarasivka and Bilohorivka in Donetsk, where six Chinese military personnel engaged Ukrainian troops. Two Chinese were taken prisoner, Zelenskyy said.

Ukraine’s Foreign Minister, Andrii Sybiha, said his ministry summoned China’s chargé d’affaires to demand an explanation, saying on X that “Chinese citizens fighting as part of Russia’s invasion army in Ukraine puts into question China’s declared stance for peace and undermines Beijing’s credibility as a responsible permanent member of the U.N. Security Council.”