Union minister for information technology and telecom, Dayanidhi Maran, today apprised Prime Minister Dr Manmohan Singh of the gravity of the fire tragedy at a private school in Tamil Nadu's Kumbakonam district, in which 90 students were charred to death yesterday.

Maran, who returned from Kumbakonam this morning, told reporters that he had also requested the prime minister to write letters to all chief ministers asking them to instruct their government machinery to take all safety measures in schools to avoid a recurrence of fire accidents.

"It is a heart-breaking incident. Sixty-five students died within an hour of the fire breaking out. Four children have 60 to 70 per cent burns and the chances of their survival are dim," he said.

He said the state government should enforce the law strictly to avoid a repeat of such incidents.

The Kumbakonam government hospital did not have an airconditioning unit and lacked fans, he said, adding that he had arranged for these  things on seeing the plight of the patients.

The burial ground did not have lights last night. There were no persons to dig pits for the burial, which added to the plight of the parents of some victims, he said.