China is "strongly dissatisfied" and "firmly opposed" to fresh US sanctions on Chinese companies over ties to Russia's war in Ukraine, the commerce ministry said Sunday.

"China urges the US to immediately stop its wrong practices and will take necessary measures to resolutely safeguard the legitimate rights and interests of Chinese companies," a ministry spokesperson said.

Washington on Friday imposed sweeping sanctions against almost 400 individuals and companies it believes are aiding Russia's war in Ukraine, including several Chinese firms, expanding existing measures to curb Moscow over the invasion of its neighbour.

According to a State Department fact sheet outlining its sanctions, these include companies in China involved in shipping microelectronics and machine tools to Russia.

The sanctions target individuals and companies both inside and outside of Russia "whose products and services enable Russia to sustain its war effort and evade sanctions," the US Treasury Department said in a statement. 

China's commerce ministry on Sunday said the move was "typical unilateral sanctions" that "disrupt international trade order and rules, hinder normal international economic and trade exchanges, and threaten the security and stability of global industrial and supply chains".

The United States has repeatedly warned China about its support for Russia's defence industry. China however, presents itself as a neutral party in the war and says it is not sending lethal assistance to either side, unlike the United States and other Western nations.

But China is a close political and economic ally of Russia, and NATO members have branded Beijing a "decisive enabler" of the war, which it has never condemned.