A six-year-old girl in Spain died and several other children were injured after a bouncy castle they were playing on flew up into the air, Spanish media reported on Monday (May 8).

The children had been playing on the bouncy castle outside a restaurant in Caldes de Malavella, near Catalonia's Costa Brava coast, British newspaper The Telegraph reported.

At least six other children were injured after the newly installed inflatable castle lifted off and landed metres from its original position outside the Mas Oller restaurant, Spanish news channel Catalunya Radio reported.

Some reports have said the castle exploded, but Catalunya Radio said the castle had not been anchored properly, with only two of six anchors holding it down.

Catalunya Radio also reported that the castle flew about 30m away from its original position, and that seven children playing on it fell to the ground and were injured.

The local mayor reportedly said the restaurant had not applied for the required licence to install the bouncy castle.

Mr Carles Puigdemont, President of Catalonia, tweeted his condolences on Monday in response to the news.

According to The Telegraph, he said in Spanish: "All my condolences to the family in this tragedy. All my solidarity and affection in these moments of such pain. Rest in peace."

Police are investigating the accident.