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.

According to the Indian government, some 400 million people were expected to attend the Maha Kumbh Mela, the most important religious event in Hinduism, held this year in Prayagraj from January 13 to February 26.

Millions of Hindus are gathering in a northern Indian city for the Maha Kumbh festival, the world’s largest religious congregation.

A deadly stampede on Wednesday hit India's Kumbh Mela, a vast Hindu festival held by the banks of the Ganges river that 400 million pilgrims are expected to visit over its six-week duration. - Sacred bathing - The Kumbh Mela,

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.

Moments before a deadly stampede at the world's biggest religious gathering in India, Hindu devotees queuing to take a spiritual bath in a river said they pleaded with police to open barricaded routes to thin out a surging crowd.

The Kumbh Mela happens every 12 years at Sangam, the confluence of three sacred rivers - the Ganges (Ganga), Yamuna and the mythical Saraswati. Hindus believe that bathing in the sacred waters will cleanse them of sins and help them attain salvation.