Saudi Arabia’s crude oil exports fell to their lowest level in at least nine years last month as attacks and security threats disrupted tanker movements through major waterways. Shipping companies are facing increased risks in both the Strait of Hormuz and the Red Sea, two important routes for global energy transportation.

The disruption has affected Saudi shipments through the Strait of Hormuz, where tanker traffic has declined amid escalating U.S.-Iran tensions. On September 1, two supertankers carrying Saudi crude were reportedly struck by unknown projectiles while sailing outbound through the strait after loading at Saudi Arabia’s Juaymah terminal. Responsibility for the attacks has not been established.