Conflict between Israel and Iran has rekindled fears of a disruption to a narrow waterway key to the global economy. Skyscraper-sized tankers ferry roughly one-fifth of the world’s petroleum, as well as massive cargoes of natural gas,

This has stoked speculation that Iran’s leadership may reach for another way to pressure its enemies to relent — blocking or effectively closing the Strait of Hormuz to shipping. This narrow waterway at the mouth of the Persian Gulf handles around 26% of the world’s oil trade.

Reports indicate three ships are transmitting not under command in the Gulf of Oman near the Strait of Hormuz. NASA's FIRMS map shows potential heat signatures, but authorities have not confirmed any incidents.