Americans are shelling out an average $3.53 per gallon for gasoline nationwide, pricey, but nothing compared with the $9.28 per gallon that motorists in Oslo are paying, CNNMoney reports. Overall, Europeans pay more than double for gasoline than what Americans pay, the news service says.

In Europe, the British, the Irish, the Germans, the Italians and the French pay somewhere between $7.50 and $8 per gallon, according to the International Energy Administration.

Danes pay even more at $8.20 per gallon, while the Greeks are forking out $8.45 per gallon.

The increase, analysts say, is not due to access to oil reserves — there's plenty in the North Sea and in nearby Northern Africa — but due to high taxes.

"The difference between countries comes down to taxes and subsidies," says Tom Kloza, the chief oil analyst for Oil Price Information Service.

"Prices are incredibly high in Europe because of the stiff taxes that EU countries put on fuel. The same holds true for many other countries."

The massive earthquake and tsunamis in Japan may jack up prices even further on both sides of the Atlantic, experts say.

If Japan cannot get its oil refineries back online quickly, then fuel supply will diminish and prices will rise.

"It's a 'yikes' situation," says James DiGeorgia, editor of the Gold & Energy Advisor, according to the Los Angeles Times.

"The sudden importation of large amounts of distilled products is expensive and it's a heavy logistics burden. That is going to drive up the market price for everything from diesel and gasoline to jet fuel."