One eyewitness wrote on social media: "Inflatable trampoline just exploded on Gorleston beach with children on it".
"Officers were called to Lower Esplanade around 11.15am following reports a child had been thrown from a bouncy castle".
The horrifying incident occurred on Sunday at Gorleston beach in Norfolk, England, when beachgoers heard a huge bang as the bouncy castle exploded.
The UK has been experiencing a heatwave in recent days, with temperatures in the Norfolk reaching 23 degrees Celsius on Sunday. She was rushed to the hospital, but could not be saved.
Superintendent Roger Wiltshire said: "We were called to a report of an inflatable trampoline apparently bursting on Gorleston beach, following a call to the ambulance service".
A witness said the contraption made of canvas and air exploded, propelling the girl 20 feet into the air.
Bruised but still standing - Merkel survives coalition migrant row
Merkel, anxious about European Union unity, opposes such a unilateral move without agreements between Germany and its neighbors. The centre-left Social Democrats, another partner in the coalition, must also accept the deal along with neighbouring Austria.
Earlier this year, a United Kingdom couple was found guilty of the gross negligence manslaughter of a girl who died when a bouncy castle she was in blew away with her trapped inside it. A man gave her cardiopulmonary resuscitation until an ambulance arrived.
Brandon Lewis, Conservative MP for Great Yarmouth, tweeted: "Absolutely tragic, thoughts are with the family and friends, just so sad".
The MP for Harlow in Essex says the government needs to look into the regulations surrounding bouncy castles.
A joint investigation into the death of the girl - who was visiting the beach with her family from Suffolk - has been launched by police and the Health and Safety Executive.
Fairground workers William Thurston, 29, and his 26-year-old wife Shelby were jailed for three years in June over the "entirely preventable" death of Summer Grant.
Summer Grant was playing on the castle when it "cartwheeled" 300 metres down a hill with her still inside.