The United States on Friday imposed sanctions on more than 400 entities and individuals for supporting Russia's war effort in Ukraine, the State Department said, including Chinese companies that U.S. officials believe are helping Moscow skirt Western sanctions and build up its military.

Washington has repeatedly warned Beijing over its support for Russia's defense industrial base and has already issued hundreds of sanctions aimed at restricting Moscow's ability to exploit certain technologies for military purposes.

Friday's sanctions include measures against companies in China involved in shipping machine tools and microelectronics to Russia, according to a State Department fact sheet outlining its sanctions against 190 targets.