They attacked the 'Hoda' oil tanker as they attempted to hijack the vessel before the Iranian Navy intervened and forced the pirates to flee the scene.
The Gulf of Aden, which links the Indian Ocean with the Suez Canal and the Mediterranean Sea, is the quickest route for more than 20,000 vessels traveling annually between Asia, Europe and the Americas.
However, attacks by heavily armed Somali pirates on speedboats have prompted some of the world's largest shipping firms to switch routes from the Suez Canal and reroute cargo vessels around southern Africa at a higher cost.