Tens of thousands of worshippers held night prayers in Mecca as millions of Muslims began arriving in Saudi Arabia before the annual haj pilgrimage, which starts on Friday (November 4).
The pilgrims bowed for prayers and circled the Kaaba, the most sacred site in Islam, at the Grand Mosque in Mecca.
As one of Islam's five pillars, the haj is enjoined on all Muslims who are physically able to carry it out, but this year the pilgrimage follows uprisings across the Arab world and growing tensions between Sunni Muslim Saudi Arabia and Shi'ite power Iran.
Although haj starts on the eighth day of the lunar month of Dhul Hijja, which falls this year on Nov. 4, most pilgrims come earlier to visit the holy mosques in Mecca and nearby Medina, where the prophet Muhammad was buried over 1,400 years ago.
Over 1.5 million pilgrims have arrived in the Mecca region so far and Saudi authorities have spent freely to avoid any repeat of the deadly incidents which marred haj seasons in the past such as fires, hotel collapses, police clashes with protesters and stampedes.
The Grand Mosque is the main attraction for over 6 million pilgrims who enter Mecca throughout the year, of which 2.5 million-3 million pilgrims are expected during the haj.