NEW DELHI - At least seven people, including a child, were charred to death while 40 others sustained burn injuries in a fire which broke out in the wee hours of Thursday on a luxury bus in the southern Indian state of Karnataka, a senior police official said.

"The mishap took place around 2.45 am (local time) when the luxury bus of Volvo make from state capital Bengaluru to Mumbai in the neighboring state of Maharashtra hit the railing of a bridge on the National Highway 4 at high speed and caught fire as its fuel tanker beneath burst," M. Shashi Kumar, police chief of Haveri district where the incident happened, told the media.

The local police chief said ?"We are yet to identify the gender of the victims as their bodies are fully burnt. Six of the injured have been rushed to a state-run hospital at Hubli, around 50 kms from Haveri, as their condition is critical due to severe burns."

Local TV channels reported that some 52 people were on board the bus and they were all asleep when the fire broke out.

State Transport Minister Ramalinga Reddy, who has rushed to the spot, said: "Over speeding appears to be the cause of the accident, as in the previous incident. We are ordering a probe to ascertain the reason though the driver could be at fault to drive so recklessly."

The mishap came barely three weeks after 45 passengers were killed in a similar bus fire at Mahabubnagar in the southern state of Andhra Pradesh.