Oil prices edged lower Friday but remained on course for a second consecutive weekly gain as hopes for a swift reopening of the Strait of Hormuz faded and Washington threatened the "toughest sanctions in history" against Iran. Brent crude futures were down 0.8% at 4:50 ET, while October West Texas Intermediate futures fell 0.89%. Brent was still set for a monthly gain of nearly 6%, following a 5.95% increase last week, and closed above $93 a barrel Thursday for the first time since July 24. The market has shifted from expecting a possible U.S.-Iran deal to pricing in weaker diplomatic prospects. Rystad Energy's Janiv Shah said refined products, particularly diesel, face greater pressure as record diesel cracks, sustained demand, thin inventories and potential near-term supply shortages raise the risk of elevated fuel costs.