Ukrainian forces are finding a growing number of components from China in Russian weapons used in Ukraine, a senior adviser in President Volodymyr Zelenskyy's office said, as Western supplies are squeezed by sanctions.

In "the weapons recovered from the battlefield we continue to find different electronics," said Vladyslav Vlasiuk, who advises the president's chief of staff on sanctions policy.

"The trend is now that there is less Western-made components but more — not hard (to) guess which country — made components. Of course, China," he said via a video call.