Picture Gallery: Mecca pilgrimage

About two million Muslim pilgrims have begun the annual rites of the hajj.

The event began without incident, but tight security was in place, with the Saudi authorities warning that they would not tolerate any attempt to exploit the event for political purposes.

Pilgrims clamber on to buses to retrace Mohammad's steps from Mecca to Mina

Devotees from more than 120 countries are taking part

Sheep are delivered for the traditional slaughter at the end of the week

Muslims are supposed to make the journey to Mecca once in their lifetime

Correspondents say there is no public debate of the fall-out from 11 September

The biggest security headache is simply ensuring the safe flow of the pilgrims