Saudi Arabia’s civil defense directorate said at least 717 people were killed in a stampede at the annual hajj pilgrimage Thursday morning.
The Saudi civil defense directorate said at least 863 other pilgrims were injured in the stampede.
The crush happened in Mina, a large valley about five kilometers (three miles) from the holy city of Mecca.
Mina houses more than 160,000 tents where pilgrims spend the night during the pilgrimage.
Photos released by the directorate on its official Twitter account showed rescue workers in orange and yellow vests helping the wounded onto stretchers and loading them onto ambulances near some of the white tents.
The Foreign Ministry in Jerusalem said it was so far unaware of any Israelis hurt, a spokesperson told The Times of Israel.
الدفاع المدني السعودي: إرتفاع عدد الوفيات إلى 150 والإصابات إلى 400 في حادثة التدافع في منى pic.twitter.com/nU6Yanw1gS
— Racha El Halabi – رشا الحلبي (@Racha93halabi) September 24, 2015
Mina is where pilgrims carry out a symbolic stoning of the devil by throwing pebbles against three stone walls.
It was not immediately clear what had caused the stampede.
Helicopters were flying over the area and the sirens of dozens of ambulances could be heard, AFP reporters said.
It was the second major incident this year for hajj pilgrims, after a construction crane collapsed on September 11 at Mecca’s Grand Mosque, Islam’s holiest site, killing 109 people including many foreigners.
Hundreds of thousands of pilgrims had converged on Mina on Thursday to throw pebbles at one of three walls representing Satan, the ritual that marks the last day of the hajj.
The world’s 1.5 billion Muslims were on Thursday marking Eid al-Adha, the Feast of Sacrifice, the most important holiday of the Islamic calendar.
The hajj is among the five pillars of Islam and every capable Muslim must perform it at least once in a lifetime.
In the past the pilgrimage was for years marred by stampedes and fires, but it had been largely incident-free for nearly a decade following safety improvements.
In January 2006, 364 pilgrims were killed in a stampede during the stoning ritual in Mina.
Thursday’s ritual was taking place at a five-storey structure known as the Jamarat Bridge, which cost more than $1 billion to build, and which was used during earlier pilgrimages.
Almost one kilometer long, it resembles a parking garage and allows 300,000 pilgrims an hour to carry out the ritual.
The faithful had gathered until dawn Thursday at nearby Muzdalifah where they chose their pebbles and stored them in empty water bottles.
They had spent a day of prayer Wednesday on a vast Saudi plain and Mount Arafat, a rocky hill about 10 kilometers (six miles) from Mina, for the peak of the hajj pilgrimage.
It was not immediately clear if the stoning ritual at Mina would continue as planned until Saturday after the stampede.
The ritual emulates the Prophet Abraham, who is said to have stoned the devil at three locations when he tried to dissuade Abraham from God’s order to sacrifice his son Ishmael.
At the last moment, God spares the boy, sending a sheep to be sacrificed in his place.
The world’s Muslims commemorated Abraham’s willingness to sacrifice his son by slaughtering cows, sheep and other animals on Thursday.
Figures released Thursday by the official Saudi Press Agency said 1,952,817 pilgrims had performed this year’s hajj, including almost 1.4 million foreigners.
Celebrations of Eid al-Adha were also marred in neighboring Yemen, where a suicide bomber struck a mosque in the capital Sanaa in an attack targeting Shiite worshippers that killed at least 25 people and wounded dozens during prayers.
There was no immediate claim of responsibility but Sanaa has been shaken by a string of bombings by the Islamic State (IS) jihadist group in recent months targeting Shiites.
Raphael Ahren contributed to this report