Prayagraj, India. At least 17 people were killed and many more injured in a stampede at the Maha Kumbh festival in northern India early Wednesday, a doctor at a government hospital said, as tens of thousands of pilgrims rushed to dip in sacred river waters during the Hindu event.

The doctor works in Prayagraj city, where over 30 injured — five in serious condition — were brought for treatment, and spoke on condition of anonymity because they were not authorized to speak with the media.

The stampede happened when pilgrims rushing to a sacred river confluence tried to jump barricades erected for a procession of holy men, Uttar Pradesh state’s top elected official, Yogi Adityanath, said in a televised statement.

Indian authorities were yet to release casualty figures, even as Prime Minister Narendra Modi acknowledged the loss of lives. Modi called the incident “extremely sad” and extended his condolences.

Wednesday was a sacred day during a six-week festival, and authorities in Prayagraj city were expecting a record 100 million devotees to engage in a ritual bath at the confluence of the Ganges, the Yamuna and the mythical Saraswati rivers. Hindus believe that a dip at the holy site can cleanse them of their past sins and end the process of reincarnation.

The main draw is the thousands of ash-smeared Hindu ascetics who make massive processions toward the confluence to bathe.

The Associated Press has made repeated attempts to confirm the death toll and total number of injuries, contacting multiple senior officials, but all said they were not authorized to release figures.

Millions continued to throng the 4,000-hectare (15-square mile) pilgrimage site despite the stampede, even as police urged them over megaphones to avoid the confluence. Adityanath urged people to instead take baths at other riverbanks.

“The situation is now under control, but there is a massive crowd of pilgrims,” Adityanath said, adding that 90 million to 100 million pilgrims were at the site.

“About 30 million people had taken the holy bath by 8 a.m. Wednesday,” he said.

Distressed families lined up outside a makeshift hospital, desperate for news of their missing loved ones. Clothes, blankets and backpacks were strewn around the site of the stampede.

“Suddenly there was pushing in the crowd, and we got trapped. A lot of us fell down and the crowd went uncontrolled,” the Press Trust of India news agency quoted pilgrim Sarojini as saying. “There was no chance for escape, there was pushing from all sides,” she said.

The Maha Kumbh festival, held every 12 years, started on Jan. 13 and is the world’s largest religious gathering. Authorities expect more than 400 million people to throng the pilgrimage site in total. Nearly 150 million people have already attended, including the likes of Defense Minister Rajnath Singh and Home Minister Amit Shah and celebrities like Coldplay’s Chris Martin.

A sprawling tent city has been built on the riverbanks to accommodate millions of visitors. It has roads, electricity and water, 3,000 kitchens and 11 hospitals.

About 50,000 security personnel are stationed in the city to maintain law and order and manage crowds, and more than 2,500 cameras monitor crowd movement and density so officials can try to prevent such crushes.

The 45-day festival is a significant cultural event for India’s Hindus, who make up nearly 80% of the country’s more than 1.4 billion people. It's also a prestige event for Modi, whose ruling Hindu nationalist Bharatiya Janata Party’s boasts of promoting Hindu cultural symbols.

The Maha Kumbh festival has been marred by stampedes in the past. In 2013, at least 40 pilgrims who were taking part in the same festival were killed in a stampede at a train station in Prayagraj.

Deadly stampedes are relatively common around Indian religious festivals, where large crowds gather in small areas. In July at least 116 people died, most of them women and children, when thousands at a religious gathering in northern India stampeded at a tent camp in Hathras town.