U.S. retail diesel reached a record nationwide average of $5.85 a gallon on Friday, up 58% from $3.71 a year earlier and nearly 9% from about $5.37 last month, according to AAA. California diesel prices reached $7.70 a gallon. The rise is intensifying inflation concerns because diesel is central to freight, agriculture, heating and industrial activity, allowing higher transport costs to feed into consumer prices. Supply strains linked to the Iran conflict, including the effective closure of the Strait of Hormuz, have compounded disruptions to Russian refining and diesel exports. Earlier estimates indicated that refinery shutdowns, Russian export restrictions and Persian Gulf shipping interruptions had removed substantial volumes from global diesel supplies while U.S. distillate inventories remained unusually low for the season. Regular gasoline also rose, with AAA putting the national average at about $4.18 a gallon on Friday, compared with about $3.20 a year earlier. Earlier reporting cited a $4.15 Friday average, creating a small discrepancy between contemporaneous readings. The White House said President Trump met with nearly a dozen refiners to discuss expanding refining capacity, while the administration's economic response has also included a Justice Department investigation into alleged gasoline price gouging. An Associated Press-NORC poll in July found 66% of respondents disapproved of the president's handling of the U.S. economy.