(NEW YORK) — As many Americans gear up to hit the road for the Fourth of July weekend, gas prices are heading back up.In the past week, the price of regular unleaded gas has shot up 6 cents a gallon across the U.S., according to the Energy Department. The national average is now $2.71 a gallon.Florida alone has seen a 12-cent increase in the past week, and in California, where the price of gas remains the most expensive, filling up your tank with regular unleaded will cost you about $3.61 a gallon.Analysts say you can blame the increase on supply and demand in the U.S. and tensions in the Middle East with Iran.Copyright © 2019, ABC Radio. All rights reserved.