More than 100 people have died in a fire at Puttingal temple in the Indian state of Kerala, police told the BBC.
The fire started about 03:30 (22:15 GMT Saturday) when an explosion was set off in a store of fireworks ready for celebrations of a local Hindu new year festival, local media reports say.
A building at the temple then collapsed, causing many of the fatalities. More than 200 are injured.
Indian Prime Minister Narendra Modi is travelling to the scene.
He tweeted that the accident in Paravur was “heart-rending and shocking beyond words”.
Many of the injured are in critical condition and are being treated at the government medical college in Thiruvananthapuram, the state capital.
Kerala police chief TP Senkumar said that many of the dead were charred beyond recognition and would have to be identified by DNA tests.
The impact of the blast was felt in houses up to a kilometre away.
“Huge pieces of concrete were flying through the air. Chunks landed in our yard,” said resident Jayashree Harikrishnan.
Kerala’s Home Minister Ramesh Chennithala has ordered an investigation into the accident.
Kerala Chief Minister Oommen Chandy is also due to visit the scene this morning.
The fireworks had been stored ready for celebrations on Thursday of Vishu, a Keralan festival marking the Hindu new year.
However, the local district magistrate had denied permission for the display to be held this year because of safety concerns and complaints from residents.
The police are planning to take action against the temple administration and the contractors who were putting on the firework display.
Fireworks and firecrackers are commonly used at temple festivals and other public events and accidents are not uncommon.