SEOUL, South Korea — A Panamanian-flagged cargo ship was sinking today off South Korea’s southeastern coast and all of its 19 crew members were missing, the coast guard said.

The 8,461-ton ship had anchored off the port city of Pohang but high waves forced it against a sea wall, South Korea’s coast guard said in a statement.

Coast guard officers said 18 Chinese and one Vietnamese were aboard the ship and were missing more than nine hours after the incident.

The officers said most of the ship had sunk and rescue efforts were being hampered by strong winds and fierce waves.

China’s official Xinhua News Agency said the ship had unloaded its freight and was to leave for Japan. The coast guard officers said the ship was carrying about 130 tons of bunker oil and diesel fuel.