Ongoing tension in the Middle East along with a switch to summer-blend gasoline are behind the uptick.

The national average price for a gallon of regular unleaded gasoline hit $2.39 on April 10, a six-cent increase from the previous week and 35 cents greater than this time last year, according to AAA. It marks the highest national average price so far in 2017.

Some 48 states and Washington D.C. are seeing higher pump prices driven by the change to more expensive summer-blend gasoline and an uptick in driving.

South Carolina ($2.11) has the least expensive gas in the nation, and Hawaii ($3.04) has the most expensive fuel prices. Kentucky saw the largest weekly increase in gas prices (+15 cents) followed by Florida (+12 cents) and Michigan (+12 cents).

AAA noted that pump prices in some West Coast states will likely hit the $3 per gallon mark by July. Gas prices in the Rockies, meanwhile, remain the most stable in the nation, with gas prices changing by only a few cents except in Colorado where prices increased seven cents over last week due to planned refinery maintenance.

Five Great Lakes and Central states saw some of the country’s most significant gas price increases. Despite having the lowest gas prices in the nation, the South and Southeast did see some big spikes in the region, such as Kentucky at an increase of 15 cents a gallon. Even as South Carolina jumped seven cents to $2.11, it still has the least expensive average in the country. Mid-Atlantic and Northeast also saw price fluctuations and will continue to see an increase in price this week.

Crude oil futures opened Monday trading at their highest level in more than a month as a result of ongoing tensions in the Middle East, including the shut down of an oilfield in Libya on Sunday after an armed group blocked a pipeline leading to an oil terminal, which could impact global supply, AAA reported.