PATNA, India — A power outage panicked crowds offering prayers on the Ganges ­River during a religious festival, sparking a stampede that killed nine children and eight other people, police in eastern India said.

Hundreds of Hindu worshippers had gathered along the riverbank in Patna, Bihar state, to pray to the sun god during the Chhath festival, according to police Superintendent Jayant Kant.

People who had crowded onto a makeshift bamboo walkway leading into the Ganges River trampled one another as they fought to get to shore, he said.

About 20 people were rushed to the hospital and about six were in critical condition, he said.

Deadly stampedes are fairly common during India’s often-chaotic religious festivals, which regularly include gatherings of tens of thousands of worshipers.

Nine people were killed in a September stampede during another festival in eastern India.