More than 10,000 Hindus flocked to the bed of Osmansagar Lake -- a key source of water in Andhra Pradesh's capital Hyderabad that dried up in April.

They held special prayers for rain Sunday, the hottest day yet this year in the city with the mercury hitting 43.9 degrees Celsius (111 Fahrenheit), around eight degrees above normal.

In the north of the province, temperatures have reached 50 degrees, producing a mounting death tolls among labourers unable or unwilling to take an afternoon off from the fields.

"This extreme heat and drought has dried up all water sources and badly affected the fishing community. Only rains can bring some respite," prayer leader G. Narsingh Rao said.

Elsewhere in the city, thousands gathered at the Miralam mosque in this historically Muslim city to seek God's help in ending the heatwave.

But despite the appeals for divine intervention, the severe heat is expected to last for a few more days, said C.V.V. Bhadram, director of Hyderabad's meteorological department.

"Strong northerly winds are sweeping across, causing temperatures to rise," he told AFP.

On Sunday another 89 people died from sunstrokes across the state, bringing the number of deaths to 884 since mid-May. Forty deaths have been reported from the heatwave in neighbouring Pakistan.