Three maritime security sources are reporting that Iranian-backed forces are believed to be behind the hijack of an oil tanker in the Gulf off the coast of the United Arab Emirates.

The British military’s United Kingdom Maritime Trade Operations (UKMTO) warned ships that “an incident is currently underway” off the coast of Fujairah. It advised extreme caution around 60 nautical miles east of the U.A.E.’s Fujairah emirate.

Hours later, the authorities said the incident was a “potential hijack,” but didn’t have any details to add.

Lloyd’s List, a leading maritime shipping authority, and Dryad Global, a maritime intelligence company, both identified the vessel involved in the incident as Panama-flagged asphalt tanker Asphalt Princess. The vessel’s owner is listed as the Emirati free zone-based Glory International.