Six people were killed on the spot and three suffered serious burn injuries in an explosion at Sriharikota High Altitude Range (SHAR) Space Centre, 120 km off Chennai, on Monday afternoon.

According to the police, the accident occurred when a rocket motor being tested caught fire and exploded while being filled with highly inflammable fuel at the Solid Propellant Space Booster Plant (SPROBP).

There were nine persons at work in the building at the time of the mishap. Six died and three were injured.

On receipt of information, security and fire personnel rushed to the spot. The dead and injured were shifted to the SHAR hospital initially. Subsequently, two of the injured persons have been shifted to a corporate hospital at Chennai.

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"The cause of the accident is being investigated. The mishap occurred between 2.30 and 3 pm. We were informed about the accident only around 5 pm," a police official told rediff.com

Four of the dead have been identified as Krishna Reddy, Bashir Ahmed, Pandit and G Srinivasulu. Two of the injured have been identified as Sachin and Krishna Prasad.

The SPROBP produces composite solid propellant for rocket motors of the SHAR Space Centre, which has recently been renamed as Satish Dhawan Space Centre.

The ISRO has ordered a high-level inquiry into the fire.

ISRO chairman G Madhavan Nair has rushed to Sriharikota to supervise operations at the centre.