Police say at least 30 people were killed and many more injured in a stampede at the world's largest religious gathering as millions of pilgrims rushed to dip in sacred waters during the Maha Kumbh festival in northern India.

Grieving families in India are cremating their loved ones while others are caring for their injured relatives in hospitals a day after a stampede

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.

Multiple casualties were feared after a stampede-like incident broke out at a Hindu religious festival, the Maha Kumbh Mela, in the northern Indian state of Uttar Pradesh on Wednesday, India's The Hindu newspaper reported early hours,

The late release of casualty figures at the gathering of millions of people was seen as shielding the political fortunes of a local leader with national aspirations.