Oil prices rose to $91 a barrel on August 18 as hopes for a Middle East peace deal faded, with Iran taking a tougher stance and the U.S. ruling out a ceasefire extension, heightening worries about energy supply. Iran will shift to a ‘fully offensive’ military posture because efforts to negotiate a permanent end to the war with the U.S. have stalled, a senior Iranian official told Reuters. Outward progress towards peace talks and a resumption of oil tanker traffic through the strategic Strait of Hormuz has ground to a halt, threatening to extend the conflict that the U.S. and Israel launched with attacks on Iran on February 28. #oil #usa #trump #iran