PHOENIX (AP) — Arizona motorists are paying more at the pump for the fourth consecutive week as they head into the Labor Day holiday weekend.

Officials with AAA Arizona said Thursday that the average statewide price for unleaded regular gasoline is $3.60 a gallon. That's up by 11 cents from last week.

This week's national average also rose 11 cents this week to $3.82 per gallon.

Triple-A officials say the price spike is due to Hurricane Isaac's threat to the Gulf of Mexico refining region this week.

Tucson has the lowest average gasoline price in Arizona at $3.53 a gallon while Flagstaff has the highest at $3.73.

Colorado has the lowest average gas prices in the continental U.S. at $3.54 a gallon with California having the highest at $4.15 a gallon.