The death of three persons at the government-run Rajaji Hospital in Tamil Nadu's Madurai on Tuesday was due to natural causes and not from disruption in oxygen supply from a power cut, a senior hospital official said on May 8.

"The three patients who were in the ICU died of natural causes on Tuesday night. They had developed cardiac problems - common in the case of severe head injuries," the hospital's dean K. Vanitha told IANS over phone.

"It is true that there was a power cut in Madurai on May 7 evening and the hospital's diesel power generator failed to kick in immediately. But all the three patients were on ventilators which were connected to batteries having power back-up of two hours," she said.

Vanitha said that the ventillators and its battery power back-up were working well and hence the deaths was not due to disruption in supply of oxygen due to lack of power. "The battery connected to the ventillators were serviced and about eight/nine patients were connected to the ventilators at that point of time... the remaining patients are fine," she said.

Relatives of the three patients had alleged that they died due to breathlessness owing to lack of oxygen supply. Asked about the three patients dying within a span of 10-15 minutes, Vanitha said that such things happen in the hospital as there are over 2,000 in-patients and over 10,000 people coming as out patients daily.

People suffering from serious head injuries from nearby districts are also brought in for treatment, she added. Vanitha also said that only three deaths happened when the power supply was cut and news reports saying five patients lost their lives are wrong.