Six newborn babies have died after a fire tore through a children’s hospital in the Indian capital, with people charging into the blaze to rescue the infants, police said on Sunday.

“All the 12 newborn babies were rescued from the hospital with the help of other people,” senior police officer Surendra Choudhary said in a statement, but adding that when they reached medical attention, six were dead.

“Legal action is being taken against the owner of the hospital,” Choudhary said.

He did not give further details on how the children died.

In addition to the six who died, another baby among the 12 brought out of the suffocating fumes was dead before the fire began, Choudhary said, without elaborating further.

The fire broke out late Saturday in the New Born Baby Care hospital in Delhi’s Vivek Vihar area.

Delhi Fire Department Director Atul Garg said 14 fire trucks were sent to battle the blaze, he told the Press Trust of India (PTI) news agency.

“The fire spread too fast due to a blast in an oxygen cylinder,” he told PTI.

Delhi Chief Minister Arvind Kejriwal called the situation “heartbreaking”.

“We all stand with those who lost their innocent children in this accident,” he said on social media.

“The causes of the incident are being investigated, and whoever is responsible for this negligence will not be spared.”