The U.S. accused Chinese companies of supporting Russia’s military.

"The United States has accused five Chinese companies of violating sanctions against Russia by continuing to support Russia’s military, and took action this week to block them from buying American technology, the Commerce Department said.

In February, U.S. authorities enacted sweeping sanctions and export controls that prohibit the sale of certain high-tech products, including advanced semiconductors, to Russia and Belarus. The addition of the Chinese companies to the export ban list shows the lengths that the Biden administration is willing to go to enforce its sanctions and could heighten tension with China over its ties to Moscow.

The companies that were added to the list on Tuesday are Connec Electronic, King Pai Technology, Sinno Electronics, Winninc Electronic and World Jetta Logistics. The Commerce Department said that these firms had continued to provide support to Russia’s military and defense industrial base and that their activities were “contrary to U.S. national security and foreign policy interests.”

“The United States and our allies and partners will continue to demonstrate our shared resolve on behalf of Ukraine by continuing to deny Russia’s military the technologies and items it needs — from whatever source attempts to supply them, wherever they are located,” Matthew S. Axelrod, assistant secretary of commerce for export enforcement, said in a statement.

The Commerce Department did not lay out the specific nature of the violations, and it has not accused the Chinese government of violating U.S. sanctions. China has been buying Russian oil as the United States and Europe have scaled back purchases, but American officials have said that so far it has been complying with the sanctions that have been imposed since February.

The addition of the Chinese companies to the export ban list followed a warning from Gina Raimondo, the secretary of commerce, who said in March that Chinese companies that defied U.S. restrictions against exporting to Russia could essentially be shut down. Companies that produce technology such as microchips that are made with American equipment and software can be crippled if they are added to the U.S. “entity list.”

The Chinese Embassy in Washington said on Wednesday that China and Russia were maintaining normal energy and trade cooperation and that China would take necessary measures to safeguard the rights of its companies.

“The unilateral sanctions and so-called ‘long-arm jurisdiction’ imposed by the U.S. on other countries in accordance with its domestic laws are against international law and basic norms governing international relations,” said Shao Hesong, a representative of the embassy."