Secretary of State Antony Blinken met with Chinese President Xi Jinping Friday and raised concerns this week with Chinese officials over the country's support for Russia.

Why it matters: Beijing has maintained warm diplomatic ties with Moscow and provided critical support to its defense industrial base as Russia has waged its war in Ukraine.

• "Russia would struggle to sustain its assault on Ukraine without China's support," Blinken said at a press conference in Beijing Friday.

Driving the news: Blinken said he reiterated the U.S.' "serious concern" over China providing weapons components to Russia during discussions with Chinese officials Friday.

• "China is the top supplier of machine tools, microelectronics, nitrocellulose — which is critical to making munitions and rocket propellants — and other dual-use items that Moscow is using to ramp up its defense industrial base," he added.
• China has also provided harbor to a U.S.-sanctioned Russian cargo ship that is believed to be carrying North Korean munitions, Reuters reported.
• Blinken did not respond to a question about whether the U.S. would be willing to impose sanctions on China over its support for Russia.

Zoom out: A senior State Department official said last week that the U.S. worries that China's support has helped Russia largely reconstitute its defense industrial base.

• This "has an impact not just on the battlefield in Ukraine but poses a larger threat, we believe, to broader European security," they added.
• Blinken echoed this concern in his remarks Friday, noting that "Beijing cannot achieve better relations with Europe while supporting the greatest threat to European security since the end of the Cold War."

The other side: China has taken issue with the U.S. for its criticism of what it says are normal trade relations between two countries.

• "It is extremely hypocritical and irresponsible for the U.S. to introduce a large-scale aid bill for Ukraine while making groundless accusations against normal economic and trade exchanges between China and Russia," Foreign Ministry spokesperson Wang Wenbin said Tuesday, AP reported.

The big picture: Blinken's meeting with Chinese officials comes as the U.S. and China have made efforts to maintain communications amid ongoing tensions.

• President Biden and Xi held a call earlier this month, their first time speaking since an in-person meeting last November.
• Blinken's trip comes shortly after U.S. Treasury Secretary Janet Yellen's visit to China.
• Despite efforts to bolster bilateral ties, Blinken told CNN in an interview Friday that the U.S. has evidence of Chinese "attempts to influence and arguably interfere" with the upcoming U.S. election.
• The State Department did not immediately respond to Axios' request for comment.

Go deeper:

• A year after Ukraine invasion, Russia's reliance on China deepens
• What Putin and Xi each get out of their "friendship"