Average retail gasoline prices in Minnesota have risen 43.1 cents in the past week, averaging $4.28 per gallon Sunday, according to GasBuddy's daily survey of 2,856 gas outlets in Minnesota. This compares with the national average that has increased 8.9 cents per gallon in the last week to to $3.67, according to gasoline price website MinnesotaGasPrices.com.

Gas prices in International Falls ranged from $4.42 to $4.44, according to the site.

“I’m very concerned about how gas prices in Minnesota have spiked following the temporary refinery closures," said U.S. Sen. Al Franken, who serves as chairman of the Energy Subcommittee on the Senate Energy and Natural Resource Committee, in a statement responding to the price increase. "Every measure should be explored to ease pain at the pump. I’m currently working with the Department of Energy to explore whether there’s a way to make sure that we can avoid having multiple temporary refinery closures in the same area of the country – which is part of the reason why we’re seeing the spike in gas prices.”

Last year, Franken introduced legislation that would direct the Commodity Futures Trading Commission to eliminate excessive oil speculation that drives up the price of gas.

A statement from Eighth District Congressman Rick Nolan said he is calling on the House Agriculture Committee and the House Energy and Commerce Committee to convene immediate hearings on the spike prior to the upcoming Memorial Day holiday.

In the statement issued along with the letters, Nolan said, “It cannot be perceived as coincidence that every year at this time, as Minnesotans plan their Memorial Day weekend vacation and fishing trips up north, the price of gas skyrockets. As every Minnesota motorist knows, the price of gasoline is out of control, it is outrageous and something must be done for the sake of our tourist industry and our economy.”

Nolan's statement continued that whether the rapid increase is due to market forces, which he says is doubtful, or whether it is due to rampant speculation and market manipulation by the oil companies, which he said is probable, “we need to get to the bottom of it and get these prices under control.”

“With that in mind, I have asked the House Energy and Commerce Committee and the House Agriculture Committee, and their appropriate subcommittees, to convene hearings at the earliest possible date to get to the truth of the matter and put these oil companies on notice that the Congress and the American people will no longer stand for this kind of unconscionable gouging.”

Including the change in gas prices in Minnesota during the past week, prices Sunday were 70.1 cents per gallon higher compared to the same day one year ago and are 85.8 cents per gallon higher than a month ago. The national average has increased 16.6 cents per gallon during the last month and stands 3 cents per gallon lower than this day one year ago.

"The national average has perked up again in the last seven days across the nation," said GasBuddy.com Senior Petroleum Analyst Patrick DeHaan. "Many motorists remain skeptical of the so called reasons that we blame higher prices on: refinery production and maintenance, tightening supply, and the now completed switch over to EPA mandated cleaner summer gasoline. Tight gasoline supply exists especially along the West Coast, and other factors are coming into play in some of the bigger metro areas where more expensive reformulated gasoline has hit pumps," DeHaan said.