Trump also teased an upcoming, undisclosed announcement on diesel and said he was considering suspending the federal gasoline tax.
Brent crude futures added 19 cents to $104.47 a barrel. US West Texas Intermediate crude futures added 36 cents to settle at $91.85.
Plans by China, the world’s top oil importer, to resume refined fuel exports after a brief halt during its Golden Week holiday, also weighed on the market. Reuters reported the development on Friday, citing sources.
Trump’s Iran pledge along with China’s resumption of product exports were moving prices lower, said PVM Oil Associates analyst Tamas Varga.
Prices have been volatile this week as threats to shipping in the Gulf and the Strait of Hormuz, which carried shipments equal to about 20% of global oil and fuel before the war, have increased.
On Thursday, Trump said Washington was having “productive discussions” with Iran and said no attack was planned before the November 3 midterm congressional elections after media reports that he was considering an attack before then.
Iran’s Tasnim news agency reported the same day that Foreign Minister Abbas Araqchi said Tehran is reviewing the US response to its proposal that would reopen the Strait of Hormuz within seven days.
The US is still pressuring Iran economically, imposing sanctions targeting individuals, networks and 17 vessels for transporting Iranian crude, oil products and petrochemicals.
The Iran war and the conflict between Russia and Ukraine have disrupted supplies of refined fuels such as gasoline, jet fuel and especially diesel fuel.
The oil market is also contending with Hurricane Isaias in the Gulf of Mexico where producers have shut in about 1.3 million barrels per day, or 62.9%, of current oil production as of Thursday, according to the US Marine Minerals Administration.