VIENNA- Five children aged between 10 and 14 were injured in northern Austria on Saturday evening when a "war relic" that was under their campfire exploded, police said on Sunday.

The children were part of a group visiting from another part of the same state of Upper Austria. The accident occurred in an area of the village of St Oswald bei Freistadt, where organized youth groups often camp, a spokesperson for the state police said.

After the explosion, police inspected an adjacent fire pit and found another object containing explosives that they also described as a "war relic", and a bomb disposal unit was called to deal with it, police said in a statement.

"Investigations are currently underway to determine how war relics came to be under the campfire area," the statement added.

The severity of the children's injuries was not immediately clear, the police said, adding that they had been taken to a children's hospital in the nearby city of Linz.

While World War Two-era bombs are still uncovered in Austria, particularly in the course of excavations for building work, accidents such at Saturday's are rare.

(Reporting by Francois Murphy; Editing by Sharon Singleton)