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.

A major rescue operation was under way in the North Sea after a cargo ship hit a tanker laden with jet fuel, engulfing both vessels in flames.

The captain of the Solong cargo ship who was arrested after crashing into an oil tanker off the English coast is a Russian national, the vessel’s owner said Wednesday, as maritime experts search for answers.