The first rituals of the annual Hajj began on Thursday (7 July).
Worshippers walked around the Kaaba, Islam's holiest site at the Grand Mosque in Makkah. Many held umbrellas to block the sun as the temperature climbed to 42C.
On Thursday, the pilgrims will move to a vast tented city at Mina, about 5 kilometers from the Grand Mosque, ahead of the main rite at Mount Arafat, where the Prophet Muhammad delivered his final sermon.
Saudi authorities have mounted a massive operation to ensure the health and safety of pilgrims. The Saudi Health Ministry has prepared 23 hospitals and 147 health centres in Makkah and Madinah, the second-holiest city in Islam, to accommodate pilgrims.
Four hospitals and 26 health centers are also ready to treat pilgrims in Mina. There are more than 1,000 beds for patients requiring intensive care and more than 200 specifically for heatstroke patients, and more than 25,000 health workers are ready to respond to cases as they arise.
After a two-year absence, international pilgrims will perform the yearly Hajj pilgrimage in Saudi Arabia after previously being restricted amid the kingdom's battle to curb the coronavirus pandemic.
One million fully vaccinated Muslims, including 850,000 from abroad, are allowed at this year's Hajj, after two years of curtailed numbers because of coronavirus pandemic restrictions.
In 2019 about some 2.5 million Muslims from around the world took part in Hajj, but after that the pandemic began. Only 60,000 fully vaccinated residents of the Kingdom took part in 2021, up from a few thousand in 2020.