By Daphne Psaledakis and Matt Spetalnick

WASHINGTON (Reuters) -The United States is preparing a sanctions package targeting more Russian oligarchs as well as their companies and assets, two sources familiar with the matter said on Wednesday, as Washington steps up pressure on Russian President Vladimir Putin over Moscow’s invasion of Ukraine.

Some sanctions could be announced as early as this week, one of the sources told Reuters, adding that details are still being worked out. Washington is also readying sanctions against more officials in Putin’s inner circle, the source said.

The U.S. Treasury Department issued new guidance on Wednesday to close loopholes it said Russia was exploiting to evade sanctions.

“Today’s guidance makes clear that such actions on behalf of Russia’s Central Bank are prohibited, closing off attempts to access the U.S. financial system,” the Treasury Department said.

Washington has repeatedly warned that it was prepared to impose further costs on wealthy Russians. The U.S. Justice Department on Wednesday launched a task force known as “KleptoCapture” aimed at straining the finances of Russia’s oligarchs.

Washington has so far imposed several rounds of sanctions, including against Putin and the central bank, after Russia’s forces invaded Ukraine in the biggest assault on a European state since World War Two. Moscow calls the assault a “special operation.”

The measures have included sanctions against what the U.S. Treasury Department said were Russian “elites,” including some with ties to Sberbank, VTB, Rosneft and the Federal Security Service (FSB).

The Washington Post, which first reported the United States was preparing to expand sanctions on Russian oligarchs, said the list of people being readied by the White House and Treasury will overlap with some of those sanctioned by the European Union on Monday, including Alisher Usmanov, the owner of an iron and steel conglomerate.

The EU on Monday imposed sanctions on 26 prominent people over Russia’s invasion of Ukraine, including oligarchs and business people active in the oil, banking and finance sectors.

It also targeted government members, high-level military people and “propagandists who contributed to spread anti-Ukrainian propaganda,” the EU said in a statement.

Several people included on the EU’s list on Monday are not yet designated by the United States, including Nikolay Tokarev, the chief executive of energy giant Transneft, Dmitry Chernyshenko, Russia’s deputy prime minister, and Kremlin spokesman Dmitry Peskov.

State Department spokesman Ned Price on Monday said that U.S. sanctions “will ultimately be symmetrical and mutually reinforcing” with those of U.S. allies and partners.

Washington has repeatedly warned that it is prepared to take further measures to hold Moscow to account over its invasion of Ukraine.

In his State of the Union address on Tuesday night, U.S. President Joe Biden said the United States would work to seize the yachts, luxury apartments and private jets of wealthy Russians with ties to Putin.

“We are coming for your ill-begotten gains,” Biden said.

The United States and its allies last week announced they would launch a task force to identify and freeze the assets of sanctioned Russian companies and oligarchs.

The White House on Wednesday said the United States is “very open” to imposing sanctions on Russia’s oil and gas industry as it also weighs the potential market impact, as global oil prices touched eight-year highs and supply disruptions mounted.

(Reporting by Daphne Psaledakis, Matt Spetalnick and Doina Chiacu in Washington; Editing by Catherine Evans, Nick Zieminski, Matthew Lewis and Cynthia Osterman)

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