At least 453 people were killed in a stampede on Thursday on the outskirts of the holy city of Mecca during the annual hajj pilgrimage, according to Saudi Arabia officials.
The crush happened in Mina, a large valley about three miles from the holy city of Mecca that has been the site of hajj stampedes in years past.
In addition to the deaths, at least 719 others were injured in the stampede, officials said.
It was the second major disaster during this year's hajj season, raising questions about the adequacy of measures put in place by Saudi authorities to ensure the safety of the roughly two million Muslims taking part in the annual religious event.
Mina is where pilgrims carry out a symbolic stoning of the devil by throwing pebbles against three stone walls, although it is not believed that Thursday’s crush happened at that exact site. The city also houses more than 160,000 tents where pilgrims spend the night during the pilgrimage.
About 4,000 rescue services personnel were participating in the operation on Thursday to help the injured and about 220 ambulances were directed to the scene, a civil defense spokesman said.
Amateur video shared on social media showed a horrific scene, with scores of bodies — the men dressed in the simple terry cloth garments worn during hajj — lying amid crushed wheelchairs and water bottles along a sunbaked street.
Survivors assessed the scene from the top of roadside stalls near white tents as rescue workers in orange and yellow vests combed the area.
Saudi authorities take extensive precautions to ensure the security of the hajj and the safety of pilgrims. But tragedies are not uncommon.
Thursday's stampede happened less than two weeks after a giant construction crane came crashing down on the Grand Mosque in Mecca, the focal point of the hajj.
That accident, on Sept. 11, killed at least 111 people and injured more than 390. Authorities blamed the crane collapse on high winds during an unusually powerful storm.
But Thursday’s stampede is the first to occur in years.
In 2006, more than 360 pilgrims were killed in a stampede at the desert plain of Mina.
Two years earlier, a crush of pilgrims at Mina killed 244 pilgrims and injured hundreds on the final day of the Hajj ceremonies.
In 2001, a stampede at Mina during the final day of the pilgrimage ceremonies killed 35 pilgrims.
The worst hajj-related tragedy, which occurred in 1990, claimed the lives of 1,426 pilgrims in a stampede in an overcrowded pedestrian tunnel leading to holy sites in Mecca.
Al Jazeera and wire services