More than 1,200 people are dead in Pakistan's deadliest heat wave on record with even more extreme heat on the way.

Some 1,233 people have been killed since the heat wave began more than a week ago, and more than 1,900 are still being treated at hospitals for heat-related issues.

The area saw some temporary relief Thursday and Friday, with temperatures dropping into the 90s, slowing the catastrophic human impact extreme heat and humidity can cause in areas with power grid issues and a lack of potable water.

(MORE: India Heat Wave, Now 5th Deadliest on Record, Kills More Than 2,300)

At its peak, the heat wave sent temperatures as high as 113 degrees Fahrenheit, combining with high humidity to make for absolutely brutal conditions.

Unfortunately, those brutal conditions returned Saturday and will stick around in the days to come, once again raising fears that the death toll could climb.

"It appears the heat is intensifying again this weekend over the south, and also expanding back into the heavily populated Punjab and northern Pakistan," said weather.com senior meteorologist Nick Wiltgen.

"An even hotter period is expected in those northern areas during the first few days of July.Where the heat and humidity intersect over the middle and lower Indus River valley, heat index values will continue to reach the 130s over the next week or more, and may exceed 140 degrees at times."

So far, the port city of Karachi suffered the worst of the heat wave. A faulty power grid, shortages of potable water and a Muslim population observing dawn-to-dusk fasting for Ramadan worsened the situation. 

Observant Muslims, who make up the majority of Karachi's 20 million residents, were abstaining from food and water during long summer days. A single sip of water invalidates the fast, but Muslims are discouraged from fasting if they are sick or if doing so would cause physical harm.

While climate scientists can't blame human-caused global warming for Pakistan's heat wave without a time-consuming study, several said it fits with what is expected from climate change.

"The deadly heat wave that has killed several hundred people in Karachi, Pakistan, is clearly a harbinger of things to come with the changing climate," said Saleemul Huq, director of the International Center for Climate Change and Development in Bangladesh and a prominent climate scientist.

"Even if this particular event cannot be unequivocally attributed to human-induced climate change, we can certainly expect such heat waves with greater frequency in future."

Just weeks ago, temperatures soared in neighboring India, killing nearly 2,200.

MORE ON WEATHER.COM: Heat Waves Bake India, Pakistan