Medical personnel tend to a wounded pilgrim following a crush caused by large numbers of people pushing at Mina, outside the Muslim holy city of Mecca September 24, 2015.[Photo/Agencies]

MINA, Saudi Arabia - At least 717 pilgrims from around the world were killed on Thursday in a crush outside the Muslim holy city of Mecca, Saudi authorities said, in the worst disaster to strike the annual hajj pilgrimage for 25 years.

At least 863 others were injured. Saudi King Salman said he had ordered a review of hajj plans after the disaster, in which two large groups of pilgrims arrived together at a crossroads in Mina, a few kilometres east of Mecca, on their way to performing the "stoning of the devil" ritual at Jamarat.

Thursday's disaster was the worst to occur at the pilgrimage since July 1990, when 1,426 pilgrims suffocated in a tunnel near Mecca. Both incidents occurred on Eid al-Adha (Feast of the Sacrifice), Islam's most important feast and the day of the stoning ritual.

Photographs published on the Twitter feed of Saudi civil defence on Thursday showed pilgrims lying on stretchers while emergency workers in high-visibility jackets lifted them into an ambulance.