At least 107 people died from lightning strikes in northern and eastern India Thursday, officials said, during the early stages of the annual monsoon season.
Some 83 people were killed in the impoverished eastern state of Bihar after being struck by lightning, and another 24 died in northern Uttar Pradesh state.
Dozens more were injured, officials said.
Lightning strikes during the June-September annual monsoon are fairly common in India.
But Bihar's Disaster Management Minister Lakshmeshwar Rai told AFP this was one of the highest daily tolls from lightning the state had recorded in recent years.
More than half of the deaths were from the flood-prone northern and eastern districts of Bihar, he added.
Rai warned the death toll could rise further as his government was still waiting on casualty reports from the interior parts of the state.
Heavy rain is forecast to hit Bihar on Friday and Saturday, according to the local India Meteorological Department office.
In neighbouring Uttar Pradesh, most of the deaths were reported in Deoria district close to the Nepal border, and the holy city of Prayagraj, authorities said.
Prime Minister Narendra Modi late Thursday tweeted his condolences to the victims' families, adding that both state governments were carrying out urgent relief work.
More than 2,300 people were killed by lightning in India in 2018 according to the National Crime Records Bureau, the most recent figures available.
The monsoon is crucial to replenishing water supplies in South Asia, but also causes widespread death and destruction across the region each year.
More than 2,300 people were killed by lightning in India in 2018 according to the National Crime Records Bureau, the most recent figures available