Jaipur: Indian army troops on Friday began efforts to put out a massive fire raging at an oil depot in western India that left at least nine people dead, 150 injured, an official said.

"Army soldiers have moved in to help firefighters who are trying to rescue the six people still trapped in the fire," said B.L. Soni, inspector general of police.

"The fire is massive. We are finding it a bit difficult to douse it," federal Petroleum Minister Murli Deora told reporters.

Dense clouds of black smoke billowed out of the oil depot as the fire soon spread to other gas tankers nearby.

Huge explosions were heard before the fire broke out and flames leaped into the sky. The blaze was visible from over 25 kilometres away, district collector Kuldeep Ranka said.

The depot, 16 kilometres south of Jaipur, capital of Rajasthan state, stores gasoline, kerosene and diesel fuel for several state-owned oil companies.

At least 150 people were in nearby hospitals and were being treated for burns and other injuries, Soni said.

People living near the depot have been evacuated and power supplies to the surrounding areas have been switched off. At least 35 firefighting teams, including some from the Indian capital of New Delhi, 350 kilometres to the north, were battling the flames, which burned through the night.

"We're asking for expert advice to help us control the fire," Ashok Gehlot, the state's Chief Minister, told reporters in Jaipur.