Friends and family searched for missing hajj pilgrims on Wednesday as the death toll at the annual rituals, which were carried out in scorching heat, surged past 900.
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, which this year fell 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.
The diplomat later added that Egyptian officials in Saudi Arabia had received "1,400 reports of missing pilgrims", including the 600 dead.
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."
Searing heat
The hajj is one of the five pillars of Islam and all Muslims with the means must complete it at least once.
Its timing is determined by the Islamic lunar calendar, shifting forward each year in the Gregorian calendar.
For the past several years the mainly outdoor rituals have fallen during the sweltering Saudi summer.
According to a Saudi study published last month, temperatures in the area are rising 0.4 degrees Celsius (0.72 degrees Fahrenheit) each decade.
In addition to Egypt, fatalities have also been confirmed by Jordan, Indonesia, Iran, Senegal, Tunisia and Iraq's autonomous Kurdistan region, though in many cases authorities have not specified the cause.
A second Arab diplomat told AFP on Wednesday that Jordanian officials were looking for 20 missing pilgrims, though 80 others who were initially reported missing were located in hospitals.
An Asian diplomat told AFP there were "around 68 dead" from India and that others were missing.
"Some (died) because of natural causes and we had many old-age pilgrims. And some are due to the weather conditions, that's what we assume," he said.
Saudi Arabia has not provided information on fatalities, though it reported more than 2,700 cases of "heat exhaustion" on Sunday alone.
Last year more than 200 pilgrims were reported dead, most of them from Indonesia.
'No news'
Each year tens of thousands of pilgrims attempt to perform the hajj through irregular channels as they cannot afford the often costly official permits.
This has become easier since 2019 when Saudi Arabia introduced a general tourism visa, said Umer Karim, an expert on Saudi politics at the University of Birmingham.
"Before, the only people who could have done that were residents of the kingdom, and they know the situation," he said.
"For these tourist visa guys, it's like being on the migrant route without any idea of what to expect."
One of the Arab diplomats who spoke to AFP on Wednesday said many of the dead Egyptians were unregistered.
Even pilgrims who have official permits can be vulnerable, including Houria Ahmad Abdallah Sharif, a 70-year-old Egyptian pilgrim who has been missing since Saturday.
After praying on Mount Arafat, she told a friend she wanted to go to a public bathroom to clean her abaya, but she never came back.
"We've searched for her from door to door and we have not found her until now," said the friend, who also spoke on condition of anonymity.
"We know many who are still searching for their family members and relatives and they are not finding them, or if they are finding them they are finding them dead," the friend added.