The US Treasury on Friday sanctioned several vessels involved in transporting Iranian oil as part of a broader crackdown on Russia's network of ships used to evade US-led energy sanctions.

Among the 183 blacklisted vessels, eight were identified as having transported both Russian and Iranian oil, according to the Treasury.

"Several of the vessels sanctioned today have shipped not only Russian oil but also sanctioned Iranian oil," the Treasury said in a statement Friday.

The vessels are part of what the Treasury described as a shadow fleet, a network employing what it called "high-risk shipping practices" to evade detection. It said many of these vessels were involved in shipping Russian oil at prices above the $60 a barrel price cap imposed by G7 countries.

“The United States is taking sweeping action against Russia’s key source of revenue for funding its brutal and illegal war against Ukraine,” said Secretary of the Treasury Janet Yellen.

In addition to targeting the vessels, the sanctions expanded to include traders, shipping companies, and maritime insurance providers linked to the illicit oil trade.

“These actions substantially increase the sanctions risks associated with Russia’s oil trade,” the Treasury said, adding that the measures reflect continued efforts to limit the financial resources of nations accused of undermining global stability.