A stampede at a train station in the north Indian city of Allahabad where the Maha Kumbh Mela festival is on has killed not less than 36 people including an eight-year-old who died while waiting for medical attention. Most of them are women.

The death toll is likely to rise as dozens of injured people have been taken to nearby hospitals. Many of them are said to be in critical condition.

The authorities are investigating the cause of the stampede but some eyewitness reports suggest the use of police force triggered panic among the pilgrims. Officials have denied the account.

The Maha Kumbh Mela festival, celebrated once in 144 years, has drawn millions of pilgrims to take a dip at the confluence of the rivers Ganges and Yamuna. Sunday was the most important day of the festival when nearly 30 million people thronged the venue known as Sangam or confluence.

"The foot-over bridge or railing did not collapse. There were a lot of people on the platform, there was a lot of rush. Enclosures for the Kumbh travellers had been created, but those enclosures were broken due to the rush. I still believe our arrangements were adequate," said Minister for Railways Pawan Kumar Bansal.

He added: "We are trying to send more trains to Allahabad even if it means cancelling trains in other areas."

Pilgrims who were present at the scene blame delay in medical attention for most of the deaths. Bansal admitted the delay saying it was caused by heavy traffic. "There was complete chaos. There was no doctor or ambulance for at least two hours after the accident," an eyewitness told the NDTV news channel.

Another victim, Gayatri, told the daily Times of India: "There was none to hear our grievances and aged people and children were the worst hit when the over-crowding resulted in commotion. We kept urging GRP [Government Railway Police] and railway authorities for help but none came."

India's Prime Minister Manmohan Singh has expressed grief over the incident and urged the authorities to take necessary steps.

"I send my heartfelt condolences to the members of the bereaved families and wish those injured a speedy recovery," said Singh.