NEW YORK (AP) — U.S. gas prices jumped back to $4 a gallon on average Monday, as Washington’s latest fighting with Iran renews strain on the flow of fuel worldwide.

According to motor club AAA, the national average for a gallon of regular gasoline is now just above the $4 mark. That’s about 13 cents more expensive than it was a week ago, and far higher than where prices at the pump stood at this time last year, when American drivers could fill up for about $3.14 a gallon on average.