U.S. benchmark crude jumped by $2.59 per barrel, or 3.5%, Thursday to $77.25, the highest level in more than a year. Brent, the international standard, gained 2.8% to $82.87 per barrel.

The rise in oil prices has already sent prices at the pump up close to 10%.

One week ago, before the U.S. and Israel attacked Iran, a gallon of regular gas was $2.98, according to auto club AAA. Today, the average price for a gallon in the U.S. is $3.25, a 9% jump.

Investors are worried over how long the war with Iran could last, how high inflation may go because of more expensive oil and how much damage that might do to corporate profits.

The broadening war in Iran will make the Federal Reserve’s job of taming prices more difficult because of the jump in oil prices, which is pushing upward on already high inflation.

That could make the central bank less likely to cut benchmark interest rates, meaning that the cost of borrowing money, for businesses and households, would remain higher than was thought even last month.

In currency trading, the U.S. dollar rose to 157.40 Japanese yen from 157.07 yen. The euro fell to $1.1617 from $1.1636.

The dollar has advanced against other currencies partly because the U.S. is viewed as facing less risk from the war than other countries, analysts said.

“When the world becomes less certain, capital gravitates toward the deepest pool of liquidity available,” Innes said, adding that the dollar “remains the market’s preferred storm shelter.”