Stolt Tankers, July 15 -- MUSCAT - The Norwegian chemical tanker Stolt Magnesium was struck by an unidentified projectile in the Gulf of Oman early Tuesday, triggering a fire in its engine room and becoming the first of three commercial vessels targeted off the Omani coast in an assault that left six crew members injured and three missing across the day's strikes.

40 local time when the Stolt Magnesium was sailing some 40 nautical miles northeast of Qalhat on the Omani coast. The company described the cause as "the explosion of an unidentified external device," expressed gratitude that all crew were safe and accounted for, and said it was "working to provide all necessary support."

The UK Maritime Trade Operations (UKMTO), the Royal Nav...