The U.S. Treasury Department announced new sanctions on Thursday on a China-based network that sells aerospace components to Iran for manufacturing drones. 

The Iran Aircraft Manufacturing Industrial Company manufactures the Shahed-136 drones and exports them to Russia, which has increasingly used them to bombard Ukraine in recent months. 

"Iran is directly implicated in the Ukrainian civilian casualties that result from Russia’s use of Iranian UAVs in Ukraine," Under Secretary of the Treasury for Terrorism and Financial Intelligence Brian Nelson said in a statement on Thursday. "The United States will continue to target global Iranian procurement networks that supply Russia with deadly UAVs for use in its illegal war in Ukraine."

Five Chinese companies and one individual were sanctioned for sending thousands of aerospace components to Iran. 

Iranian drones have been used by Russia to strike Ukrainian civilian structures and critical infrastructure. 

US SLAPS NEW SANCTIONS ON RUSSIA OVER UKRAINE WAR, RAISES TARIFFS

White House National Security Adviser Jake Sullivan warned earlier this year that Iran "could potentially be contributing to widespread war crimes" by supplying Russia with drones to bombard Ukraine. 

"Their weapons are being used to kill civilians in Ukraine and to try to plunge cities into cold and darkness," Sullivan said in January. 

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U.S. officials have even accused Iran of sending personnel to Crimea to train Russian troops on how to pilot the drones. 

"They can lie to the world, but they certainly can't hide the facts, and the fact is this — Tehran is now directly engaged on the ground," National Security Council spokesperson John Kirby said last fall. 

Fox News Digital's Greg Norman contributed to this report.