Gasoline prices rose overnight, pushing Monday's national average above $4.06 a gallon, the highest price American motorists have faced since July 2008, according to auto club AAA.

Calls are increasing for the United States to ban imports of Russian oil, and that is adding to prices that were rising long before Russia's invasion of Ukraine. The conflict, however, has helped push U.S. gasoline prices up 45 cents a gallon in just the past week.

The price of regular broke $4 a gallon on Sunday for the first time in nearly 14 years and is now up nearly 50% from a year ago.

Prices for gasoline in Europe is even higher, averaging 1.75 euros per liter last week, according to the European Commission, the equivalent of $7.21 per gallon.

GasBuddy, which tracks prices down to the service-station level, said Monday that the U.S. was likely to break its previous record price of $4.10 a gallon, but that does not account for inflation. In today's terms, the record price would be equal to about $5.24 after accounting for inflation.

"Forget the $4 per gallon mark, the nation will soon set new all-time record highs and we could push closer to a national average of $4.50," said GasBuddy analyst Patrick De Haan. "We've never been in this situation before, with this level of uncertainty ... Americans will be feeling the pain of the rise in prices for quite some time."

In late-morning trading, benchmark U.S. crude was up 3% to around $119 a barrel, and the international price gained 4% to around $123 a barrel. Major U.S. stock indexes were down more than 1%.