New U.S. sanctions took “sweeping action” against Russia’s energy sector on Friday.

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

Newsweek reached out to President-elect Donald Trump‘s transition team via email for comment on Friday.

Why It Matters

President Joe Biden has been a huge ally to Ukrainian President Volodymyr Zelensky in his fight against Russian President Vladimir Putin‘s full-scale invasion that began nearly three years ago.

With less than two weeks until the Biden administration leaves the White House, it has placed new sanctions, which it called the most significant to date, on Russia’s oil and liquefied natural gas sectors, the driver of the eastern Europen county’s economy. Officials said the sanctions could cost the Russian economy over billions of dollars per month.

What To Know

Over 180 oil-carrying vessels that are suspected to be part of a shadow fleet used by Russia to evade oil sanctions, opaque Russian oil traders, Russian-based oil field service firms and Russian energy officials are targeted by the new sanctions.

The sanctions also block U.S. entities from doing business with the sanctioned entities.

U.K. Sanctioned Russia

The United Kingdom joined the U.S. in sanctioning two of Russia’s major oil producers, Gazprom Neft and Surgutneftegas, and dozens of the firms’ subsidiaries on Friday.

The U.K.’s Foreign Office said that the two firms produce a combined total of over 1 million barrels of oil a day, which is worth $23 billion a year.

What People Are Saying

Kremlin spokesman Dmitry Peskov said ahead of the anticipated announcement of the new sanctions, according to The Associated Press (AP): “We are aware that the administration will try to leave as difficult legacy in bilateral relations as possible for Trump and his team.”

U.S. Treasury Secretary Janet Yellen said in her Friday statement: “This action builds on, and strengthens, our focus since the beginning of the war on disrupting the Kremlin’s energy revenues, including through the G7+ price cap launched in 2022. With today’s actions, we are ratcheting up the sanctions risk associated with Russia’s oil trade, including shipping and financial facilitation in support of Russia’s oil exports.”

British Foreign Secretary David Lammy said, according to the AP: “Oil revenues are the lifeblood of Putin’s war economy,” adding, “Taking on Russian oil companies will drain Russia’s war chest – and every ruble we take from Putin’s hands helps save Ukrainian lives.”

White House national security spokesman John Kirby said, according to the AP that the Biden administration chose to slap these sanctions on Russia now because concerns about world oil markets have let up.

“This was really based on market conditions,” Kirby said, adding, “So the time was propitious for this decision, and that’s why the president made it.”

What Happens Next

Trump will be inaugurated on January 20 and after that, it will be up to his incoming administration whether to keep the new sanctions or get rid of them, according to Biden administration officials. It’s unclear how Trump plans to handle the Russia-Ukraine war, but he has said that if he were at the negotiating table with Putin and Zelensky, the war would end “within 24 hours.”

The president-elect has already met with Zelensky, and he told reporters on Thursday that Putin “wants to meet, and we are setting it up.”

This article includes reporting from The Associated Press.