At least 17 people were killed and many more injured in a stampede at India's Maha Kumbh festival, the world's largest religious gathering, a doctor at a government hospital said, as tens of thousands of pilgrims rushed to dip in sacred river waters during the Hindu event.

It was not immediately clear what triggered the panic at the festival where devotees from across India had congregated to bathe at the confluence of the Ganges, the Yamuna and the mythical Saraswati rivers.

At least 30 people have been killed and many more were injured in a stampede at the world’s largest religious gathering in India, police said. The tragedy took place as millions of pilgrims rushed to dip in sacred waters during the Maha Kumbh festival in the north of the country.

Millions continued to throng the site even as police urged them to avoid the area. Deadly stampedes are relatively common around Indian religious festivals, where large crowds gather in small areas.

Hindu devotees and mystics have gathered in the northern Indian city of Prayagraj for the Maha Kumbh festival, which is the largest religious congregation on Earth. Nearly 400 million people

Indian opposition leader Rahul Gandhi condemned organisers for "mismanagement" and a "focus on VIP movement" which he blamed for the deaths. Others, including Prayagraj local Rekha Verma, pointed the finger at heavy-handed tactics by "rude and abusive" police officers to keep immense throngs of devotees in line.