LONDON (Reuters) - Most of the jet fuel onboard the U.S.-flagged tanker Stena Immaculate that was hit by a container ship in a collision off Britain's coast remains contained and only two of the vessel's 18 fuel tanks have leaked, owner Stena Bulk said on Wednesday.

A cargo ship struck an anchored tanker in the North Sea, engulfing both vessels in flames and rupturing a cargo tank filled with jet fuel. One seafarer was hospitalized and the other 36 mariners across both crews were safe and accounted for,

U.K. police say the Solong cargo ship's captain, identified by the vessel's owner as a Russian national, was detained on suspicion of negligent manslaughter.