The average price of a gallon of regular-grade gasoline rose 9 cents nationally over the past two weeks, to $2.43.
Industry analyst Trilby Lundberg said Sunday that increased oil prices and the U.S. missile strike on a Syrian air base contributed to the rise.
She says that unless oil prices retreat quickly, consumers should expect gasoline prices to climb a few more cents.
The national average is up 33 cents per gallon over the price a year ago.
Gas in San Francisco was the highest in the contiguous United States at an average of $3.01 a gallon Friday. The lowest was in Jackson, Mississippi, at $2.09 per gallon.
The U.S. average diesel price is $2.58, up 1 cent from two weeks ago.