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.

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.

People were trampled as pilgrims at the Maha Kumbh Mela, one of the world’s biggest gatherings, gathered where the Ganges and Yamuna Rivers meet.

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.

Several people were feared dead after a stampede at the Maha Kumbh Mela, or Great Pitcher Festival, in northern India's Uttar Pradesh State on Wednesday, on one of the holiest days of the event as tens of millions of people gathered at the site.