Washington DC - The US on Thursday said Chinese President Xi Jinping cannot both improve ties with the West and support Russia after he vowed to boost relations with his counterpart Vladimir Putin.

"The People's Republic of China can't have its cake and eat it too," State Department spokesman Vedant Patel told reporters.

"It can't have it both ways and want to have [better] relationships with Europe and other countries while simultaneously continuing to fuel the biggest threat to European security in a long time," Patel said, referring to Russia's invasion of Ukraine.

The US has charged that China – while not directly sending weapons to Russia – has supported Moscow's largest defense industry expansion since Soviet times, a concern raised by Secretary of State Antony Blinken on a visit to Beijing last month.

China Xi warns Biden of China's "red line" and addresses transition to Trump in final meeting

Xi and Putin framed their nations' ties as a stabilizing force as they met Thursday in Beijing, where the Russian president is seeking greater Chinese backing for his war effort.

Chinese support for Russia's defense industry "not only threatens Ukrainian security, it threatens European security," Patel said.

Xi, in remarks broadcast on Russian television, said that China "looks forward to the early restoration of peace and stability on the European continent."

Asked about China's stated support for a peace process, Patel said, "From our point of view, the solution is simple – the Russian Federation can just leave Ukraine."