US diesel prices have hit a record high, with the national average reaching $5.85 a gallon, driven up by the ongoing US-Israel war with Iran, which has disrupted global oil supplies. The increase, which has pushed diesel above the peak seen after Russia's invasion of Ukraine, is squeezing American households and businesses and has become a political liability for President Trump ahead of November's midterm elections, with his approval rating and public support for the conflict both slipping.

Diesel now costs $5.85 a gallon on average, up from $3.71 a year ago, while petrol has climbed to $4.15 from $3.20, according to the American Automobile Association. Iran's effective closure of the Strait of Hormuz, through which a fifth of the world's oil passes, has tightened supply, and price rises vary by region, with Western states such as Washington paying $6.81 a gallon. In response, Trump has struck an oil deal with Venezuela to develop 17 fields holding an estimated 65bn barrels, promising to lower prices, though analysts are sceptical it will overcome the barriers that have long deterred investment there.