April 22 (UPI) -- An Iranian gunboat attacked and badly damaged a container ship close to the Strait of Hormuz on Wednesday with a second cargo vessel fired on, Britain's maritime security agency said.

The master of an unidentified container ship reported that the vessel was in the western approaches to the strait, about 15 nautical miles off the coast of Oman when an Islamic Revolutionary Guard Corps gunboat approached and opened fire without warning, the Royal Navy's Maritime Trade Operations center said in an alert.

The ship sustained "heavy damage to the bridge" but there was no fire or environmental impact and the crew was safe.

No attempt to make VHF radio contact was made before the gunboat fired on the vessel, said UKMTO.

There were no details or information regarding the ship, but CBS News said it was the Greek-owned Epaminondas.