While nationwide diesel prices at the pump saw a decrease this week, it was a small one. The average price for a gallon of diesel fell only four-tenths of a cents to $3.967, according to the weekly U.S. Energy Information Administration's Gasoline and Diesel Fuel Update.

Some regions have seen an increase in diesel prices this week, including regions along the East Coast and in the Midwest. Diesel prices jumped the most, 2.3 cents, in the Lower Atlantic region to $3.94 a gallon, which is still below the national average.

Diesel still tops $4 per gallon in the Rocky Mountain Region and on the West Coast. The highest prices for diesel can be found in California, where the average price per gallon is $4.14.

Gasoline prices also continued to decline this week as the nationwide average price per gallon dropped 2 cents to rest at $3.43. Prices did see a slight increase in the Midwest region, 1.3 cents, according to the report, the only region in the U.S. to see an increase in gasoline prices this week.

The Huffington Post reports that the price for benchmark crude closed at its highest point since Oct. 22 at $89.28. Reasons cited for the rise in price of oil are concerns about current unrest between Isreal and Hamas in the Middle East, and - to a lesser degree - the U.S. "fiscal cliff" situation.