New Delhi (CNN) Food shared among participants in a religious ceremony is believed to have caused at least 11 deaths and put more than 90 worshipers in hospital, police in the southern Indian state of Karnataka said Saturday.

The religious food offering, or "prasad," involved was vegetable rice. "We believe the 'prasad' was poisoned," Dharmender Kumar Meena, Police Superintendent of Chamarajanagar district, told CNN.

"There was a foundation-laying ceremony of a new Hindu temple and following the event the 'prasad' was distributed. People started vomiting shortly after," Meena said.

Samples of the food have been sent to a laboratory for examination, Meena said.

Indian policeman inspect the kitchen of a temple on Saturday after the incident.

Of those hospitalized, 29 are in a critical condition, the head of the Chamarajanagar district administration, B.B. Cauvery, told CNN. Many of them have stomach pain and "most of them are showing symptoms of nausea and dehydration," she said.

Read More