Devonport, Australia - Five children have died and four are being treated in hospital, with some critically injured, after a bouncy castle accident in the Australian state of Tasmania, police said on Thursday.

Wind picked up a bouncy castle and threw it into the air at an end-of-year activity day at a primary school in Devonport, in the state's north-west, Tasmania Police said in a midday (local time) statement.

"Several children fell from a height of about 10 meters [32 feet] around 10 AM and are currently receiving medical treatment at the scene as well as in hospitals," the statement added.

Police spokesperson Darren Hine said the victims were two girls and two boys.

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Later, a further child from Hillcrest Primary School was reported to have died following the accident by broadcaster ABC, citing the police.

The police said their thoughts were with the families and loved ones of those involved.

Multiple helicopters responded to the incident while police and emergency services were also on the scene, the authorities said.

The school was closed and parents rushed to the scene to collect their children, Australian broadcaster ABC reported.

"My heart is breaking for all those impacted by the tragedy at Hillcrest Primary School in Tasmania today," Prime Minister Scott Morrison said in a tweet.

"My prayers are with the family and friends of the children who lost their lives, the injured, the first responders and all those who witnessed this deeply distressing event."