WASHINGTON (AP) — The Treasury Department imposed sanctions Wednesday on a Chinese refinery accused of purchasing more than $1 billion worth of Iranian oil, saying the proceeds help finance both Tehran's government and Iran's support for militant groups.

The sanctioned refinery in China's Shandong province received dozens of shipments of crude oil from Iran worth more than $1 billion, the Trump administration said. Some of the petroleum came from a front company for Iran’s paramilitary Revolutionary Guard, U.S. authorities said.

Officials also announced that several companies and vessels involved in the shipments were added to the sanctions list.

The new penalties were imposed by the Office of Foreign Assets Control and follow earlier efforts by the administration to disrupt the flow of Iranian oil, which authorities say is carried by Iran's “shadow fleet." The United States has already penalized dozens of individuals and vessels involved in the shipments.

“Any refinery, company, or broker that chooses to purchase Iranian oil or facilitate Iran’s oil trade places itself at serious risk,” Treasury Secretary Scott Bessent said in a news release. "The United States is committed to disrupting all actors providing support to Iran’s oil supply chain, which the regime uses to support its terrorist proxies and partners.”

Iran is accused of backing militant groups including Yemen's Houthis, who have launched attacks on international shipping, Hezbollah in Lebanon and Hamas in Gaza.

During his confirmation hearing earlier this year, Bessent criticized the Biden administration’s sanctions policies and called for the U.S. to have a more “muscular” sanctions system, including on Iran and Russian entities and oil.

Tammy Bruce, a State Department spokeswoman, said in a statement Wednesday that Trump “is committed to drive Iran's illicit oil exports, including to China, to zero.”

“As Long as Iran attempts to generate oil revenues to fund its destabilizing activities, the United States will hold both Iran and all its partners in sanctions evasion accountable,” Bruce said.

The new sanctions were announced the same day that Iran confirmed that the next round of talks with the U.S. on Tehran's nuclear program will be held in Rome.

Messages seeking responses from representatives of the Chinese and Iranian governments were not immediately returned Wednesday.