The sanctions target the network for "facilitating the shipment of millions of barrels of Iranian crude oil worth hundreds of millions of dollars to the People's Republic of China," the Treasury Department wrote in a statement.

The oil was shipped on behalf of Iran's Armed Forces General Staff and a sanctioned front company called Sepehr Energy Jahan Nama Pars, the Treasury statement noted.

"The Iranian regime remains focused on leveraging its oil revenues to fund the development of its nuclear program, to produce its deadly ballistic missiles and unmanned aerial vehicles, and to support its regional terrorist proxy groups," said Treasury Secretary Scott Bessent.

"The United States is committed to aggressively targeting any attempt by Iran to secure funding for these malign activities," he added.

The Treasury's actions follow President Trump's recent decision to reinstate his so-called "maximum pressure" campaign against Iran over allegations that it is trying to develop nuclear weapons.

Trump signed a memorandum on Tuesday reimposing the tough policy of sanctions against Iran, similar to those he levied during his first term, adding he hoped he would not "have to use it very much."

The memorandum instructs every department in the US government to design sanctions on Iran, especially in relation to nuclear activities, a White House aide told Trump at the signing ceremony.