South African health officials say 11 people have died of heatstroke after a weeklong heatwave across the country.

Provincial spokesman Tebogo Lekgethwane said Sunday that eight people died on Thursday as temperatures passed 40 degrees Celsius (104 degrees Fahrenheit) in the North West province. Three more people died on Friday, and 16 others were hospitalized, AP reported.

According to the South African Weather Service, the North West province reached record temperatures this week, with the highest at 45 degrees Celsius (113 degrees Fahrenheit). The weather service warned that high temperatures may give way severe thunderstorms in the coming week.