"It's disturbing with the Chinese soldiers having been captured," State Department spokeswoman Tammy Bruce told reporters.

"China is a major enabler of Russia in the war in Ukraine. China provides nearly 80 percent of the dual use items Russia needs to sustain the war," she said.

"Continued cooperation between these two nuclear powers will only further contribute to global instability and make the United States and other countries less safe, less secure and less prosperous," she said.

The United States, since the administration of Joe Biden, has taken China to task for sending Russia dual-use items, which can be used for civilian or military purposes.

China, while hailing its relationship with Russia, has publicly steered clear of directly backing the war in Ukraine.

President Donald Trump has called for prioritizing efforts to counter China and has sought to negotiate an end to Russia's invasion of Ukraine.