At least one person is dead after a tree fell on a group of youths camping in tents during a storm in the town of Rickenbach in south-west Germany, police said early Wednesday.

The boys were part of a group of 21 people, including four minders, who were camping out near Rickenbach, on the Swiss border in Germany's southwestern corner.At least four other youths were seriously injured in the incident, one of them critically.

Authorities believe that a lightning strike during a storm caused the tree to fall on the camp.

It's unclear how many were staying overnight in the camp at the time of the incident, authorities said.