U.S. diesel prices hit an all-time high

The U.S. diesel price has reached a historic high, creating a fresh problem for President Donald Trump as energy markets face pressure from multiple directions.

The national average climbed to $5.85 per gallon on Friday, according to The Wall Street Journal. A year ago, diesel cost an average of $3.712 per gallon.

The increase comes as the wars in Iran and Russia unsettle energy markets. Transport through the Strait of Hormuz has been affected by the conflict in the Middle East, even though the waterway normally carries large volumes of oil and fuel. Russia has also restricted diesel exports after several Ukrainian drone attacks on its refineries. Bloomberg reported that the export ban has been extended through September.

Those disruptions have pushed more buyers toward the United States, increasing demand for American diesel and driving prices higher. Diesel powers trucks, ships, tractors and construction equipment, and it is also used for heating. A prolonged rise could therefore make food, construction projects and transportation more expensive. Bloomberg said it could also make it harder for the Federal Reserve to bring inflation under control.

Trump has asked refineries to increase production, but many plants are already operating close to full capacity. Bloomberg described the price pressure as a potential political challenge for the White House, with two months remaining before the U.S. midterm elections.