File photo: an oil vessel explodes in Saudi Arabia

An explosion rocked an oil ship off Saudi Arabia’s port city of Jeddah on the Red Sea, with the owners saying it was hit by an external object.

Dryad Global, a maritime intelligence firm, reported on its website that the explosion occurred on an oil tanker at 2211 GMT on Sunday.

“Reports indicate that a vessel has experienced an explosion whilst carrying out operations within the main tanker anchorage at the Saudi Aramco Jeddah Port,’’ the firm said.

Later Shipping company Hafnia said that one of its oil tankers had been hit by an unidentified external source that caused fire and explosion while the ship was discharging at Jeddah port in Saudi Arabia.”

The crew has put out the fire and no one was injured, the company said.

The cause of the blast is not yet known, but according to maritime security consultancy Dryad Global it may have been a limpet mine attack.

The United Kingdom Marine Trade Operations, an organisation under Britain’s Royal Navy, urged ships in the area to exercise caution and said investigations were ongoing.