Islamabad: A devastating weeklong heatwave in Pakistan's southern port city of Karachi has killed 1,233 people, an official said.

Nazar Mohammad Bozdar, operations director at the Provincial Disaster Management Authority, said about 65,000 heatstroke patients were treated by doctors at all of Karachi's hospitals since June 20 when the heat wave struck Sindh province, where Karachi is the provincial capital.