Local media reported that some of the children died due to a lack of oxygen supply. The hospital denied the allegations.
At least 64 children have died over six days at a government hospital in northern India that suffered oxygen shortages, officials said Saturday.
Authorities have launched an inquiry into the causes of the oxygen disruption but denied reports that it had caused the deaths at the Baba Raghav Das Hospital (BRD) in Gorakhpur, Uttar Pradesh state.
TRT World's Arabella Munro has more on the story.
Indian media said 30 children died on Thursday and Friday because of the lack of oxygen on wards. Suppliers' bills had allegedly not been paid.
"Sixty patients have died at the hospital in the last five days but we don't think it's linked to reports of oxygen shortage," Anil Kumar, Gorakhpur's divisional commissioner said.
State health minister Sidharth Nath Singh announced later that four more deaths had been reported Saturday, taking the toll to 64 over the six days starting Monday.
Singh denied that any of the deaths were linked to the oxygen shortage.
Twenty-three children died on Thursday, when, according to a statement shared by the office of state chief minister, "the pressure of the liquid oxygen supply became low and 52 reserve oxygen cylinders were pressed into service".
The office of Prime Minister Narendra Modi said on Twitter that Modi was "monitoring the situation in Gorakhpur" and was in touch with state authorities. Modi's conservative nationalist party controls the state.
TRT World spoke to journalist Ishan Russell in New Delhi.
The Hindustan Times newspaper on Saturday described chaotic scenes at the hospital as oxygen supply was disrupted.
"Even as 90 jumbo oxygen cylinders were pressed into service to maintain the supply on Friday, the hospital ran out of oxygen around 1.00 am," it said.
"All hell broke loose," the report added.
"What followed was complete chaos as panic-stricken relatives of patients ran for help, and with the support of hospital staff tried to maintain supply of oxygen... using artificial manual breathing bags (AMBB).
"However several patients started collapsing due to inadequate supply," it added.
The uncle of an 11-year-old girl, Vandana, who died at the hospital, echoed local media reports about the chaos.
"We didn't know what was happening at the time. The staff just told us to keep pressing AMBB after every count till three. We kept doing that for some time," he told ABP news channel.
The region is one of India's poorest and registers hundreds of child deaths each year from Japanese Encephalitis and Acute Encephalitis Syndrome, which is rife in parts of eastern and northern India.
"We will be getting more liquid oxygen cylinders tonight or tomorrow, and have also cleared the dues of the supplier," district official Kumar said.
He added that the deaths could be due to "natural" causes, as many patients admitted are in "serious" condition.
India's Nobel Peace laureate Kailash Satyarthi, a campaigner for children's rights, described the deaths as "a massacre" on Twitter.
"Thirty kids died in hospital without oxygen. This is not a tragedy. It's a massacre. Is this what 70 years of freedom means for our children?" he said.
The state's health minister suspended the hospital's top official, holding him accountable for the oxygen supply until the completion of a formal investigation.
"The reasons for the disruption of oxygen supply are being investigated but our probe has revealed that no deaths happened because of it," Singh told reporters after a visit to the hospital.
"When you hear about around 23 deaths in a day, it shocks you, and it should," he said.
"But the average daily death toll for the month of August (at the hospital) has been 19 to 22 for the last three years," the minister added.
The deaths have sparked a political firestorm as opposition politicians sought to pin the blame on Modi's Bharatiya Janata Party, which rules the state.
The hospital is located in Gorakhpur district, which is represented by Uttar Pradesh chief minister Yogi Adityanath, who was appointed to head the state this year.
"The current government is responsible for the deaths of children in Gorakhpur due to the lack of oxygen. Strict action should be taken," tweeted former Uttar Pradesh chief minister Akhilesh Yadav.
State government officials in TV appearances chastised opposition leaders for seeking to politicise the issue.