Several people are missing after two freighters collided near the German North Sea island of Heligoland, the central command for maritime emergencies said on Tuesday.
The Polesie and Verity vessels collided at around 0300 GMT about 12 nautical miles (22 kilometres) southwest of Heligoland, likely causing the Verity to sink, central command said in a statement.
One person was rescued from the water and is receiving medical treatment, while several others are still missing, it added.
The rescue operation includes a rescue cruiser, police boats, a sensor aircraft and a helicopter, among other vessels.
The Polesie, which was carrying 22 passengers, is still waterborne, according to the authorities.
The Verity was on its way from Bremen to the English town of Immingham. The Polesie was sailing from Hamburg to La Coruna in Spain.