MINA, Saudi Arabia — A horrific stampede ****** at least 717 pilgrims and ******* hundreds more Thursday on the outskirts of the holy city of Mecca in Saudi Arabia, the deadliest tragedy to ****** the annual hajj pilgrimage in more than two decades.

At least 863 pilgrims were ******* in the crush, said the Saudi civil defence directorate, which provided the ***** toll. The tragedy struck as Muslims around the ***** marked the start of the Eid al-Adha holiday.

It was the second major ******** 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 2 million Muslims taking part. A crane collapse in Mecca nearly two weeks earlier left 111 people ****.

Saudi Arabia takes great pride in its role as the caretaker of *****’s holiest sites and host to millions of pilgrims annually. But the hajj poses an immense logistical and security challenge for the kingdom given the sheer number of hundreds of thousands of people — from differing linguistic and cultural backgrounds, many of whom have saved for years for a once-in-a-lifetime opportunity — intent on following the same set of rituals at about the same time.

Thursday’s crush happened in Mina, a large valley about 5 kilometres (3 miles) from Mecca that has been the site of hajj stampedes in years past.

Mina is where pilgrims carry out a symbolic stoning of the devil by throwing pebbles against three stone columns. It also houses more than 160,000 tents where pilgrims spend the night during the pilgrimage.

Thursday’s tragedy struck during a morning ***** of pilgrims at the intersection of streets 204 and 223 as the faithful were making their way toward a large structure overlooking the columns, according to the Saudi civil defence directorate.

The multi-story structure, known as Jamarat Bridge, is designed to ease the pressure of the crowds and prevent pilgrims from being trampled.

Ambulance sirens blared as rescue crews rushed the ******* to nearby hospitals.

More than 220 rescue vehicles and some 4,000 members of the ********* services were deployed soon after the stampede to try to ease the congestion and provide alternative exit routes, according to the directorate.

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 ******* wheelchairs and water bottles along a sunbaked street.

********* assessed the scene from the top of roadside stalls near white tents as rescue workers in orange and yellow vests combed the area.

International media covering the hajj, including The Associated Press journalists in Mina, were restricted from visiting the site of the ******** for several hours and from immediately leaving an Information Ministry complex where the press is housed during the final three days of the pilgrimage per government rules.

Photos released by the directorate on its official Twitter account showed rescue workers helping the ******* onto stretchers and loading them onto ambulances near some of the tents.

Some 2 million people are taking part in this year’s hajj pilgrimage, which is an obligation of every able-bodied ******. The pilgrimage began in earnest Tuesday.

Saudi authorities take extensive precautions to ensure the security of the hajj and the safety of pilgrims. There are about 100,000 security forces deployed this year to oversee crowd management and ensure pilgrims’ safety during the five-day pilgrimage.

At Mina specifically, authorities have put measures in place over the years to try to alleviate the pressure posed by masses of pilgrims converging on the site of the stoning ritual.

Officials use surveillance cameras and other equipment to limit the number of people converging on the site, and the Jamarat Bridge has multiple exits to facilitate the flow of people.

But tragedies are not uncommon.

The ***** toll from Thursday’s crush far exceeded that of a similar ******** in 2006, near the same site, when more than 360 pilgrims were ****** in a stampede. Another stampede at Mina in 2004 left 244 pilgrims **** and hundreds *******.

The deadliest hajj-related tragedy happened in 1990, when at least 1,426 pilgrims perished in a stampede in an overcrowded pedestrian tunnel leading to holy sites in Mecca.

The latest tragedy is certain to have touched many different countries as the ******* likely included pilgrims of different nationalities.

At least 41 Iranian pilgrims perished and at least 60 were ******* in Thursday’s crush, according to the chief of the Iranian hajj organizing agency. Saeed Ohadi blamed Saudi Arabia for “safety errors” and said in comments to Iranian state TV that “mismanagement by the Saudis” led to the tragedy.

Thursday’s crush 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. The Sept. 11 ******** ****** at least 111 people and ******* more than 390.

Authorities blamed the crane collapse on high winds during an unusually powerful storm, and faulted the construction giant Saudi Binladin Group, which oversees construction at the mosque, ******* following operating procedures.