The ongoing violence in Iraq and concerns that it may impact global oil supplies helped drive up fuel prices this week across the U.S. – though such worries are easing at the moment.

“All eyes in the oil market remain focused on the situation in Iraq,” noted Denton Cinquegrana, chief oil analyst for the Oil Price Information Service (OPIS), in a statement. “It's impossible to know where prices will go, but if history has taught us anything, we're in for a wild ride. There's even talk from some analysts of gasoline, diesel, jet and crude prices reaching 2008 highs.”

According to data tracked by the Energy Information Administration (EIA), average retail pump prices for diesel and gasoline increased in almost every region of the country this week.

The national average for diesel increased 3.7 cents to $3.919 per gallon, which is 8.1 cents higher compared to the same week in 2013, the agency noted.

Diesel prices increased in every region of the country and exceeded the $4 per gallon mark in four of them: California, up 5 cents to $4.119 per gallon; New England, up 1.4 cents to $4.102; the Central Atlantic, up 1.9 cents to $4.071; and the West Coast, up 5.9 cents to $4.053.

EIA added that, without California in the mix, average diesel pump prices on the West Coast increased 7 cents to $3.973 per gallon – the largest increase in diesel recorded by the agency this week.

The national average for gasoline jumped 1.8 cents this week to $3.704 per gallon, which is 12.7 cents higher compared to the same week in 2013, the agency said.

Average retail pump prices for gasoline increased in every region of the U.S. except the Midwest, where prices fell 2.1 cents to $3.693 per gallon.

The Rocky Mountain region witnessed the largest price increase this week, a 7.6 cent surge to $3.606 per gallon, followed by the Gulf Coast with a 6.6 cent spike to $3.499 per gallon.

The West Coast recorded highest prices for gasoline this week, at $4.011 per gallon when California is included (a 1.2 cent jump compared to last week) and at $3.853 per gallon when California’s prices are removed from the mix (a 3.3 cent jump compared to last week.)