A once-in-12-year Hindu festival, Maha Kumbh, the world's largest religious gathering, is being held in Prayagraj, norther

Hindu devotees, mystics and holy men and women have gathered in India's northern city of Prayagraj for the Maha Kumbh festival, the world's largest religious gathering.

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 seven people were killed and around 10 injured in a pre-dawn stampede at the Maha Kumbh Mela in the northern Indian city of Prayagraj on Wednesday, an official said, the most auspicious day of the six-week Great Pitcher Festival.

A tragic stampede at the Maha Kumbh festival in northern India has left several people dead and many others injured.