Some 3 million Muslim pilgrims ascended Mount Arafat near Mecca in Saudi Arabia at the climax of the annual haj.
Authorities deployed around 100,000 security personnel to secure the pilgrims, the state-run Saudi Press Agency reported.
The granite hill is the place where the Muslim prophet Mohammed is said to have delivered his last sermon around 14 centuries ago.
The pilgrims wear seamless white robes to symbolize equality during the haj, one of the five pillars of Islam. It culminates in the feast of Eid al-Adha on Tuesday.
Saudi officials on Sunday said 1.3 million pilgrims arrived from abroad – 21 per cent less than last year. No reason was given for the decline.
The pilgrimage comes as the Middle East Respiratory Syndrome -Coronavirus (MERS-CoV) has been slowly spreading in parts of the region.
At least 136 cases, including 58 deaths, have been reported since last month. Sporadic outbreaks have been limited to Jordan, Saudi Arabia, Qatar and the United Arab Emirates.
The risk of the spread of illness or stampedes in Saudi Arabia is present during the haj.
In 2006, nearly 350 pilgrims were killed in a stampede.
In 1987, more than 400 people were killed when police attempted to break up a political rally. Saudi authorities have since warned pilgrims to avoid political activities during the pilgrimage. – dpa