More than 700 pilgrims killed in crush in worst hajj disaster for 25 years

Muslim pilgrims cast stones at pillars symbolizing Satan, during the annual Haj pilgrimage on Eid al-Adha in Mina, near the holy city of Mecca September 24, 2015.[Photo/Agencies]

Efforts to improve safety at Jamarat have included enlarging the three pillars and constructing a three-decker bridge around them to increase the area and number of entry and exit points for pilgrims to perform the ritual.

More than 100,000 police and thousands of video cameras are also deployed to allow groups to be dispersed before they reach dangerous levels of density.

"Please pilgrims do not push one another. Please leave from the exit and don't come back by the same route," an officer kept repeating through a loudspeaker at Jamarat.

Two weeks ago 110 people died in Mecca's Grand Mosque when a crane working on an expansion project collapsed during a storm and toppled off the roof into the main courtyard, crushing pilgrims underneath.