At least three patients on ventilator support at Madurai Government Rajaji Hospital in Tamil Nadu died on Tuesday night, allegedly due to a power cut. The kin of the deceased subsequently protested outside the hospital to demand action against the hospital staff, the Hindustan Times reported on Wednesday.

The deceased have been identified as Mallika, 55, Palaniyammal, 60, and Raveendran, 52. Their relatives alleged that two more patients on ventilator support are battling for life. Unidentified police officials told PTI that a total of five patients have died at the medical facility.

Mallika had suffered an aneurysm and had been operated at another hospital before being transferred to the Madurai Government Rajaji Hospital, The News Minute reported. Palaniammal was admitted due to a head injury. Raveendran had suffered a serious brain injury in a fall.

“It was a 15-bedded emergency ward for accidental care of the Madurai Government Hospital near Anna bus stand in Madurai,” Murugesan, a relative of Mallika, said. “When the thunderstorm happened, the power cut made the ventilators stop working.”

Hospital Dean Vanitha Mani, Madurai City Assistant Police Commissioner Sasi Mohan, Medical Superintendent Raja and Resident Medical Officer Sri Latha are negotiating with the protesting relatives, the Hindustan Times said.

Vanitha Mani denied that the patients died due to the power cut. “While it is true there was a power cut late in the evening, we had restored power immediately with the help of power back up,” she said. “The deceased patients have not died due to ventilator failure. They were critical when their relatives brought them here from other private hospitals.”

Vanitha Mani told The News Minute that the ventilators continued to function when the electricity was cut between 6.20 pm and 7.20 pm. She added that 10 other patients who were on ventilator support had survived.

As many as 18 patients on ventilator support at the Madras Institute of Orthopaedics and Traumatology Hospital in Chennai had died in December 2015 during floods in the city. The deaths were the result of power failure and lack of oxygen cylinders.