A seven-year-old boy and his mother both died after falling into the Baltic Sea during a ferry crossing from Poland to Sweden, Polish police said on Friday.

The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. 

The sea stretches from 53°N to 66°N latitude and from 10°E to 30°E longitude.

The two Polish citizens went overboard while travelling from Gdansk to Karlskrona on Thursday, a police spokesman told Poland’s TVN24 broadcaster.

According to Swedish rescuers, the child fell first into the water and his mother jumped in afterwards.

The bodies of the passengers were found in the evening during a search of the area.