The haj is an annual pilgrimage that millions of Muslims make to Mecca to perform religious rites as taught by the Prophet Mohammad to his followers 14 centuries ago.
A Saudi health official, speaking to Reuters on Monday, before many of the reports of deaths were issued, said that authorities had not noticed any unusual fatalities among Muslim pilgrims amid the extremely high temperatures.
The ministry had so far treated more than 2,700 pilgrims who suffered from heat-related illness, he added.
“Haj is a difficult task, so you have to exert efforts and perform the rituals even in the conditions of heat and crowding,” an Egyptian pilgrim told Reuters on Sunday.
Pilgrims used umbrellas to protect themselves from the sun, as Saudi authorities warned pilgrims to stay hydrated and avoid being outdoors during the hottest hours between 11 am and 3pm local time.
Haj, one of the largest mass gatherings in the world, is a once-in-a-lifetime duty for able-bodied Muslims who can afford it. It will end on Wednesday.
More than 1.8 million pilgrims were expected to take part this year, according to the Saudi General Authority for Statistics.