TITUSVILLE/HOUSTON: Two top US Energy Department officials said on Tuesday they were working with refiners at home and abroad to boost fuel output as a diesel shortage has raised prices, driving dissatisfaction among voters with the White House ahead of the November midterm elections.

Diesel prices have jumped to record highs because of disruptions from the Iran war and Ukrainian attacks on Russian refineries . Retail diesel prices averaged about US$6.32 a gallon on Tuesday, according to motorist group AAA.

The Trump administration has taken several steps to try to lower fuel prices that have surged since the start of the Iran war on Feb 28, including relaxing restrictions on Russian diesel exports, invoking the Defense Production Act to boost output and allowing commercial vehicles to run on red-dyed diesel normally limited to off-road equipment.