NEW DELHI — Thirty children have died at a public hospital in India over the past two days, with government critics blaming a shortage of oxygen after a supplier of liquid oxygen cut off deliveries because of unpaid bills.

Government officials were scurrying to explain what had happened, admitting that the state-run hospital owed more than $50,000 to a supplier of liquid oxygen and that oxygen supplies had been “disrupted.”

“There was some payment issue to the oxygen supplier, and there was a shortage of liquid oxygen,” said Anil Kumar, the commissioner of the city of Gorakhpur. But, he added, “those deaths were not due to lack of oxygen.”

Other officials said the hospital had a backup oxygen supply, though they did not explain why so many children had died in such a short time. Since Monday, a total of 60 children have died at the hospital, many from acute encephalitis and others in the neonatal unit.

The hospital, Baba Raghav Das Medical College, is in Gorakhpur, several hundred miles east of New Delhi, India’s capital. It is the rainy season in India, when officials say it is not unusual for as many as 10 children to die there every day from Japanese encephalitis, a mosquito-borne disease.

While the cause of the deaths remained unexplained — by officials, at least — India’s health care system is often unsparing when it comes to payments. This week, Indian newspapers carried an account of a man who suffered a severe head injury in a motorcycle accident and was turned away from half a dozen hospitals, apparently after they determined he would not be able to pay his bills.

The man was a poor farmhand, and the ambulance driver trying to help him said hospital officials turned the victim away after asking about his financial background. For seven hours, the man was driven from hospital to hospital before arriving at a government one, where he was declared dead on arrival.

Government officials have brought charges of culpable homicide in the case of the motorcyclist, and officials in Gorakhpur said they were opening an inquiry into why so many children had died in the past two days.

Government officials said that by Friday morning, they had found new supplies of oxygen for the hospital.

Opposition politicians instantly seized on the deaths, calling the government insensitive. “The state government is responsible for the deaths,” said Raj Babbar, a leading opposition figure. “How can there be shortage of oxygen?”

Other opposition leaders demanded that the government pay $30,000 to compensate each family. Next week is India’s 70th anniversary of independence from Britain, and some scholars made the connection.

“This is not a tragedy. It’s a massacre,” said Kailash Satyarthi, a children’s rights advocate and winner of the Nobel Peace Prize. “Is this what 70 years of freedom means for our children?”