MECCA, Saudi Arabia (AP) -- Hundreds of thousands of Muslim pilgrims piled into -- and on top of -- buses on their way to a ritual of solemnity, prayer and reflection Friday, a key part of the annual hajj.

From midday until after sunset, pilgrims will stand praying and reflecting on their lives at Mount Arafat, where Mohammed, Islam's chief prophet, gave his last sermon 14 centuries ago.Some two million pilgrims swathed in simple white robes made their way Thursday to the plain of Mina, six miles north of Mecca, where Mount Arafat is located. Some walked, others held tightly to the roofs of crowded buses. The hajj chant of "Here I am. Oh, Almighty, here I am," reverberated across Mecca.

This year's ritual takes place on Islam's holy day, Friday, for the first time since 1994, giving this year's hajj the status of a "greater pilgrimage."

Around 1.2 million Saudis are participating in this year's hajj, the annual pilgrimage to Mecca, which involves performing set rituals over a series of days. All able-bodied Muslims are required to perform the hajj at least once if they can afford it.

A Saudi official said Thursday that fewer foreigners have come this year, attributing the drop to economic troubles in southeast Asia and among oil producing countries.