Four crew members were killed and five others are missing after a collision early Friday between two freighters off the coast of Chiba Prefecture in the Pacific Ocean sank one of the vessels, the Japan Coast Guard said.

The accident took place around 5:10 a.m., some 18 km south of Cape Inubosaki, where visibility was low due to dense fog, the coast guard said. The accident caused an oil spill.

Sunk in the accident was the Wei Hang 9, a 3,947-ton freighter registered in Malta with 21 crew members, the coast guard said.