Multiple students in a primary school in the Australian city of Sydney have been injured after a classroom science experiment went wrong.

Reports say at least two students were rushed via ambulance to a hospital with serious burns. Nine others are believed to have suffered superficial burns.

Initial reports suggest the experiment involved sodium bicarbonate and methylated spirits, said outlet 9news.

Helicopters, paramedics and fire trucks were seen responding on scene.

The incident took place at Manly West Public School around 13:00 local time (02:00 GMT) on Monday.

New South Wales Ambulance Acting Superintendent Phil Templemen said the wind impacted the experiment and blew around some of the chemicals that were used.

The children – believed to be aged between 10 and 11 according to reports – suffered burns to their bodies, including on their face, chest, lower abdomen and legs, said the Sydney Morning Herald (SMH).

One teacher was also treated for minor injuries.

One resident told the SMH that a teacher had come out to speak to a group of people who had gathered outside.

“The teacher who addressed us said it was a science experiment that went wrong and some chemical burns were involved,” said Tyson Atkins.

One popular school science experiment that can be found online, called the Carbon Sugar Snake, uses methylated spirits and baking soda, also known as sodium bicarbonate.

It involves mixing sugar with baking soda, placing a small amount of the mixture in sand soaked with methylated spirits, and igniting the concoction.

However, it is not yet clear what kind of experiment the school had conducted.