The Group of Seven wealthy democracies said Saturday that they plan to release 100 million barrels of oil and fuel products in the coming weeks from their emergency reserves, starting with “substantial” amounts of diesel after the fuel recently hit record high prices in the United States.

US President Donald Trump said the diesel release would happen “immediately,” echoing a G7 promise to start “immediately” with a “frontloaded substantial release” of diesel within the next 20 days and the rest over four months.