The captain of a cargo ship that collided with a U.S. tanker is a Russian national who remains in U.K. police custody, the vessel's owner said Wednesday.

The 59-year-old man, who hasn't been named by authorities, was arrested by police in northeast England on Tuesday on suspicion of manslaughter by gross negligence over the collision. He hasn't been charged.

Shipping company Ernst Russ, which owns the Portugal-flagged cargo vessel Solong, said that the ship's 14 crew were a mix of Russian and Filipino nationals.

U.K. authorities say they don't suspect foul play in the crash.

The cargo ship collided Monday with MV Stena Immaculate, a tanker transporting jet fuel for the U.S. military in the North Sea off eastern England on Monday, setting both vessels ablaze. One sailor from the Solong is missing and presumed dead. The other 36 crew members from the two vessels were brought safely ashore, with no major injuries.

The 596-foot Stena Immaculate was operating as part of the U.S. government's Tanker Security Program, a group of commercial vessels that can be contracted to carry fuel for the military when needed.

The collision sent jet fuel pouring into the sea and sparked fears of significant environmental damage. Environmentalists said that oil and chemicals posed a risk to sea life, including whales and dolphins and to birds, including puffins, gannets and guillemots that live on coastal cliffs.