Relatives scoured hospitals and pleaded online for news, fearing the worst after temperatures hit 51.8 degrees Celsius (125 Fahrenheit) in Mecca, Islam’s holiest city, on Monday.
About 1.8 million people from all over the world, many old and infirm, took part in the days-long, mostly outdoor pilgrimage, held this year during the oven-like Saudi summer.
An Arab diplomat told AFP that deaths among Egyptians alone had jumped to “at least 600”, from more than 300 a day earlier, mostly from the unforgiving heat.
That figure brought the total reported dead so far to 922, according to an AFP tally of figures released by various countries.
Mabrouka bint Salem Shushana of Tunisia, in her early 70s, has been missing since the climax of the pilgrimage on Saturday at Mount Arafat, her husband Mohammed told AFP on Wednesday.
Because she was unregistered and did not have an official hajj permit, she was unable to access air-conditioned facilities that allow pilgrims to cool down, he said.
“She’s an old lady. She was tired. She was feeling so hot, and she had no place to sleep,” he said. “I looked for her in all the hospitals. Until now I don’t have a clue.”
Facebook and other social media networks have been flooded with pictures of the missing and requests for information.
Those searching for news include family and friends of Ghada Mahmoud Ahmed Dawood, an Egyptian pilgrim unaccounted for since Saturday.
“I received a call from her daughter in Egypt begging me to put any post on Facebook that can help track her or find her,” said one family friend based in Saudi Arabia, who spoke on condition of anonymity because he did not want to anger Saudi authorities.
“The good news is that until now we did not find her on the list of the dead people, which gives us hope she is still alive.”