A six-year-old girl in Spain has died and six other children have been injured after a bouncy castle reportedly exploded and flew into the air.

The incident occurred behind the Mas Oller restaurant in Caldes de Malavella, north east Spain, according to Spanish police.

The children had been playing on the bouncy castle when the incident happened, causing the six-year-old girl to be thrown 45 feet into the air, Sky News reports.

The girl suffered serious injuries and later died in the intensive care unit of a nearby hospital.

A seven-year-old girl and a nine-year-old boy were airlifted to hospital after suffering multiple injuries. The girl underwent surgery and is reportedly in a stable condition.

The children injured in the incident are aged between three and 11.

Local reports suggest the explosion occurred when a valve on the inflatable castle failed and caused pressure to build up. Police also reported that the castle had only been held down by two of its stakes, causing it to fly into the air.

The castle rose above the restaurant as it came free and landed some 130 feet away. Officials said the restaurant did not have the proper licence for the installation.