Brent crude rose 4.3% to $104.48 a barrel on Thursday amid escalating fears that attacks on commercial tankers in the Strait of Hormuz are disrupting global oil shipments.
Only seven tankers crossed the Strait of Hormuz on Tuesday, less than half the average of the previous seven days, following a record ten attacks between September 28 and October 4.
Oil majors Shell and Chevron reduced production and evacuated nonessential workers as Hurricane Isaias moved toward the US Gulf Coast, creating additional supply and refining risks.