Oil prices slid at the start of trading on Monday morning, a respite from the volatility of recent weeks as Russia’s assault on Ukraine grinds on.
Brent crude, the international benchmark, was trading at about $107 a barrel, down roughly 5 percent. In December, it cost about $65 a barrel, before Russia’s president, Vladimir V. Putin, began what President Biden called a “vicious war of choice” in Ukraine. West Texas Intermediate, the American benchmark, was trading around $103, down almost 6 percent.
Oil prices, which surged last week as the markets braced for American sanctions, are showing signs of leveling out. On Tuesday, President Biden shut off the spigot of Russian oil into the United States as punishment for the war in Ukraine. He also banned the import of Russian natural gas and coal.
Mr. Biden had initially resisted calls for such aggressive sanctions on Russian oil, concerned that they would push fuel prices higher — a potentially polarizing issue in an election year. But as Russia escalated its attacks on Ukraine, he announced sweeping sanctions, which he warned would inevitably bring more pain at the pump for Americans.
“I said I would level with the American people from the beginning,” he said last week. “And when I first spoke to this, I said defending freedom is going to cost.”
The average price of a gallon of gas was $4.325 on Monday, according to AAA. That is up from a week earlier when gas prices hit $4.009, nearly the highest level since 2008, but unchanged from Sunday.
Even before Mr. Biden’s decision, the United States imported only a small amount of Russian oil, representing less than 10 percent of its total energy resources. But the step, intended to further economically isolate Russia, effectively prevents the country from profiting from American oil purchases.