The Biden administration on Friday targeted Russia’s energy sector, including its oil industry, with some of its harshest sanctions to date meant to cut off funding for Moscow’s war against Ukraine.

The U.S. Treasury imposed sanctions on Gazprom Neft and Surgutneftegas, which explore for, produce and sell oil as well as 183 vessels that have shipped Russian oil, many of which are in the so-called shadow fleet of aging tankers operated by non-Western companies. The sanctions also include networks that trade the petroleum.

The Biden administration on Friday imposed its broadest package of sanctions yet targeting Russia's oil and gas revenues in an attempt to give Kyiv and the incoming administration of Donald Trump leverage to reach a deal for peace in Ukraine.