At least eight people died and 80 were injured Tuesday in a giant explosion at a firework factory in India that saw balls of flames soar into the sky, officials said.

Footage on Indian television showed a tower of flame after the explosion at the firecracker plant, with dozens of ambulances sent and army helicopters called in to evacuate the wounded.

Senior district police official Rajeshwari Mahobia told AFP there were "eight deaths so far and around 80 injured", at the factory in Harda in Madhya Pradesh state, adding that "the death toll is likely to go up".

Madhya Pradesh Chief Minister Mohan Yadav said reports of the explosion were "very sad news" and said medics at burn units in nearby major hospitals had been asked to "make necessary preparations".

"Ambulances are being rushed to Harda from the surrounding areas, and the army has been contacted to arrange for helicopters," Yadav said in a post on X, formerly Twitter.

At least 20 ambulances were at the site, with 50 more being sent to help those injured, he added.

Dr Manish Sharma, a surgeon at the Harda district hospital, said the centre had been flooded with a stream of casualties.

"We have eight deaths at our hospital, a total of 90 people were admitted here so far and we have referred 15 of them to a bigger hospital," Sharma told AFP.

"As more people are being rescued from the site, they are being brought here."

- 'Stampede' -

Kailash Chand Parte, a senior district official who is coordinating rescue efforts from the factory, said fire engines were battling the fierce blaze.

"The fire is still not under control and we have around 15 fire engines and many rescue workers at the site", Parte said.

He said around 200 to 300 people worked at the factory, but it was not known how many were inside at the time of the explosion.

"At least 10 buildings around the complex where the blast happened have been damaged because of the intensity of the explosion", he added.

One policeman told the Times of India that the dead included those trampled during the panic to escape the raging flames.

Some died during the "stampede after the blast", local police officer Abdul Raees Khan told the newspaper, adding rescue teams were "yet to reach the actual blast site as (the) fire is on".

Explosions often occur in firecracker workshops in India.

Fireworks are hugely popular in India, particularly during the Hindu festival of Diwali, as well as for use during wedding celebrations.

But many factories fail to stick to basic safety requirements and operate without permits.

In 2019, at least 18 people were killed in a firework factory explosion in Batala in Punjab state, and another 10 were killed in the same year in Bhadohi in Uttar Pradesh.