Japanese Mitsui O.S.K. Lines Ltd said on Thursday it has hired a military attack specialist to help it investigate the cause of damage to a tanker in the Strait of Hormuz.
The supertanker was diverted to a UAE port on Wednesday where officials said the damage, which stirred fears of an attack in the straight, was caused by a freak wave.
But a Mitsui O.S.K. company official said at a news briefing in Tokyo that the damage was unlikely to have been caused by an earthquake-related wave. It will begin a full-fledged investigation on Thursday.
Japan's Transport Ministry said on Wednesday there was an "explosion" at around 00:30 a.m. local time and cited the possibility of an attack on the ship, but port officials said there was no evidence.
No oil leaked from the very large crude carrier, named M. Star, although some members of the 31-strong crew were injured.
Forty percent of the world's seaborne oil passes through the narrow Strait of Hormuz, gateway to the oil-producing Gulf, where Al Qaeda has threatened to attack shipping.
The tanker, bound for Chiba, near Tokyo, is carrying around 2.3 million barrels of Qatar Land and Abu Dhabi Lower Zakum crudes, industry sources have said.