The death toll after a floor collapsed at a Hindu temple in India had risen to 35 on Friday, with rescue operations underway to find one person still missing, a local official told AFP.

Dozens of worshippers celebrating a major religious holiday plunged into the stepwell -- a stair-lined communal water source -- on Thursday after the floor covering it collapsed in the central city of Indore.

"Thirty-five people are dead. One person is still missing. Rescue operations are on," Indore district magistrate Ilayaraja T. told AFP by phone.

A witness at the scene told AFP that rescuers were working to determine whether or not one more person reported missing had also fallen down the well.

Women, children and an 18-month-old baby were among those standing on the grill covering the well when it buckled and gave way, plunging them into about 7.5 metres (25 feet) of water, the Times of India newspaper reported.

Prime Minister Narendra Modi said Thursday he was "extremely pained" by news of the accident.

"The state government is spearheading rescue and relief work at a quick pace," he added. "My prayers with all those affected and their families."

Modi's office said compensation payments of 200,000 rupees ($2,400) would be given to the next of kin.

Narottam Mishra, home minister of Madhya Pradesh state, told reporters on Thursday that an investigation had been launched into the mishap.

Television footage on Thursday showed emergency workers using ropes and ladders to reach those trapped in the well in Madhya Pradesh state.

Other videos showed the caved-in floor and mangled steel bars as well as police officers using ropes to seal the area.

Temples across India were brimming with devotees on the occasion of Ram Navami, the birthday of the Hindu deity Lord Ram.

Deadly accidents are common at worship sites in India during major religious festivals.

At least 112 people died in 2016 after a huge explosion caused by a banned fireworks display at a temple marking the Hindu new year.

The blast ripped through concrete buildings and ignited a fire at a temple complex in Kerala state where thousands had gathered.

Another 115 devotees died in 2013 after a stampede at a bridge near a temple in Madhya Pradesh.

Up to 400,000 people were gathered in the area, and the stampede occurred after the spread of a rumour that the bridge was about to collapse.

About 224 pilgrims died and more than 400 others were injured in a 2008 stampede at a hilltop temple in the northern city of Jodhpur.