U.S. diesel prices hit a record high on Friday, hitting $6.06 a gallon according to motorist group AAA. 

The price jumped from $5.98 on Thursday and $5.85 a week ago. The Iran war is the biggest factor in the surge in prices as crude oil traffic through the Strait of Hormuz continues to be limited. 

“This has been not a spike but a sustained grind higher,” the energy analyst Rory Johnston told the Financial Times. “We don’t really have anywhere near enough diesel on the market.”

Farmers and the agriculture sector feel the brunt of the soaring prices. Diesel oil powers combines, tractors, and irrigation equipment. Businesses that rely on delivery services are also feeling the pain, absorbing higher freight costs inevitably passed onto the consumer. 

President Donald Trump has argued that the rising energy prices are a necessary cost to make sure Iran does not acquire a nuclear weapon. Speaking at the Republican midterm convention in Dallas Wednesday, Trump said “oil will be going down as soon as we win the war with Iran, which is taking place.”