More than 2.5 million Muslims will witness the annual hajj pilgrimage on Friday in the Islamic holy city of Makkah, Saudi Arabia, against a backdrop of tensions in the Gulf.
Crowds of worshippers have already begun to gather in Makkah in the days ahead of the hajj, the focal point of the Islamic calendar.
More than 1.8 million visitors had arrived by midday local time on Tuesday, authorities said amidst gulf tensions.
Crowds of faithful from across the world wore flowing white robes as they descended on to the holy city. The pilgrims will undertake religious rites that have remained unchanged since the founding of Islam 14 centuries ago.