Story highlights Hundreds more are discovered dead in Sindh Province

Saturday's temperature reached 44.8 degrees Celsius (112.64 degrees Fahrenheit)

The heat wave strikes as most Pakistanis are observing Ramadan

Islamabad, Pakistan (CNN) The death toll soared to 748 people in Pakistan's heat wave after authorities began counting deaths in the province surrounding Karachi, officials said Wednesday local time.

Authorities earlier reported 323 deaths in only Karachi in the three-day heat disaster.

But more deaths were reported by officials in the Sindh Province, said National Disaster Management Authority spokesman Ahmed Kamal.

Officials also told CNN that the number of patients treated for heat stroke in Jinnah hospital, the largest in the Karachi, is 2,360. Karachi, a seaside city, is Pakistan's largest.

Photos: Pakistan's deadly heat wave Photos: Pakistan's deadly heat wave Covered corpses from a devastating heat wave lie in a mortuary in Karachi, Pakistan, on June 26. The death toll from the heat wave in Sindh province topped 1,000, officials told CNN. Hide Caption 1 of 13 Photos: Pakistan's deadly heat wave A Pakistani child pours water on his cattle to cool off during a hot afternoon in Peshawar on Thursday, June 25. Hide Caption 2 of 13 Photos: Pakistan's deadly heat wave Pakistanis bring a heatstroke victim to a hospital in Karachi on Thursday, June 25. More than 1,000 people have died in a heat wave in southern Pakistan, officials say. Hide Caption 3 of 13 Photos: Pakistan's deadly heat wave A patient suffering from heatstroke receives treatment at a Karachi hospital on Wednesday, June 24. Hide Caption 4 of 13 Photos: Pakistan's deadly heat wave Pakistanis receive ice during the heat wave in Karachi on June 24. Hide Caption 5 of 13 Photos: Pakistan's deadly heat wave A man awaits medical help for his daughter who is suffering from dehydration due to the extreme weather in Karachi on June 24. Hide Caption 6 of 13 Photos: Pakistan's deadly heat wave A man helps move a heat wave victim to a Karachi hospital on Monday, June 22. Hide Caption 7 of 13 Photos: Pakistan's deadly heat wave Pakistanis rest at the mosque during the heat wave in Karachi on June 22. Hide Caption 8 of 13 Photos: Pakistan's deadly heat wave A Pakistani man cools down at a mosque during the heat wave in Karachi on June 22. Hide Caption 9 of 13 Photos: Pakistan's deadly heat wave A Pakistani man rests at a mosque during the heat wave in Karachi on June 22. Hide Caption 10 of 13 Photos: Pakistan's deadly heat wave Pakistani volunteers and relatives prepare to shift the bodies of heat wave victims into the cold storage of the Edhi morgue in Karachi on June 22. Hide Caption 11 of 13 Photos: Pakistan's deadly heat wave Pakistanis cool off at a river outside Islamabad on Sunday, June 21. Hide Caption 12 of 13 Photos: Pakistan's deadly heat wave Relatives mourn the death of a heat wave victim at the Edhi morgue in Karachi on June 21. Hide Caption 13 of 13

At least one city morgue, CNN affiliate Geo.tv has reported, has been overwhelmed with the numbers of dead.

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