The only survivors in the bus, four children below 12, were critically injured, said police officer Fakirappa, who uses one name.
The family was heading to Ajmer on a Muslim pilgrimage in western India, he said.
The accident took place near Madarpur village in Kurnool district, 240 kilometres (150 miles) south of Hyderabad, the Andhra Pradesh state capital.
“The driver was apparently sleepy while driving in the wee hours and he lost control of the vehicle.” Fakirappa said.
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The minibus collided with the truck coming from the opposite direction, ripping off part of its body and leaving the victims tangled inside. Their bodies were retrieved with the help of cutters, he said.
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More than 110,000 people are killed every year in road accidents across India, according to police. Most crashes are blamed on reckless driving, poorly maintained roads and ageing vehicles.