The death toll from the severe heatwave in southern Pakistan over the past week has climbed to 1,233, despite cooler temperatures bringing some relief to residents, officials said.

In Karachi, Pakistan's economic centre of around 20 million people, the temperature only reached 34C on Saturday, after touching 45C at the peak of the heatwave last week.

Nazar Mohammad Bozdar, operations director at the Provincial Disaster Management Authority, said on Saturday that 65,000 heatstroke patients were treated at the city's hospitals since June 20.

Bozdar told the AP news agency that 1,923 patients with heat-related ailments are still being treated.

The victims of the heatwave have died of heat stroke, dehydration or other heat-related illnesses - with the elderly and poor the worst-affected groups.

At the height of the crisis last week, Dr Seemin Jamali, a senior official at the Jinnah Postgraduate Medical Centre (JPMC), Karachi's largest government hospital, told Al Jazeera that the centre's mortuary was "overflowing".

"They are piling bodies one on top of the other," Jamali said at the time.

The heatwave struck Karachi at a time when the city's Muslim majority was observing the dawn-to-dusk fasting month of Ramadan, further worsening the situation.

Repeated power outrages across the province, and particularly in Karachi, exacerbated the situation. Some Karachi residents told Al Jazeera they were without electricity for more than 12 hours everyday, making it nearly impossible to find respite indoors.