Nearly 40 bodies were brought to a hospital morgue after a stampede at the Maha Kumbh Mela in northern India on Wednesday, three police sources told Reuters, as tens of millions gathered to bathe in sacred river waters on the most auspicious day of a six-week festival.

Bodies were still being brought to the local Moti Lal Nehru Medical College hospital morgue more than 12 hours after the tragedy at the world’s biggest gathering of humanity, though the government was yet to officially announce the casualty numbers.

“More bodies are coming in. We have nearly 40 bodies here. We are transferring them out as well and handing over to families one by one,” one of the sources said.

Senior police officer Vaibhav Krishna, when contacted for comment, said police could not give the official numbers because they were busy with crowd management.

Distraught relatives queued up to identify those killed by the stampede, which occurred when crowds surged towards the confluence of three rivers, where immersion is considered particularly sacred.

Some witnesses spoke of a huge push that caused devotees to fall on each other, while others said closure of routes to the water brought the dense crowd to a standstill and caused people to collapse due to suffocation.

“There was commotion, everybody started pushing, pulling, climbing over one another. My mother collapsed…then my sister-in-law. People ran over them,” said Jagwanti Devi, 40, as she sat in an ambulance with the bodies of her relatives.

An official at Prayagraj’s SRN Hospital, where some of the injured were taken, said those who died had either suffered heart attacks or had comorbidities like diabetes.

“People came in with fractures, broken bones…Some collapsed on the spot and were brought dead,” said the official, who did not want to be named.

Prime Minister Narendra Modi offered condolences to “devotees who have lost their loved ones” and said local officials were helping victims “in every possible way”, without specifying the number of dead.

Yogi Adityanath, chief minister of Uttar Pradesh state where the festival city of Prayagraj is located said the stampede was set off when some devotees tried to jump barricades put up to manage crowds between 1 a.m. and 2 a.m. (1930-2030 GMT Tuesday) near the arena of the ascetics.

At the scene, people sat on the ground crying, while others stepped over belongings left by those trying to escape the crush.