Mecca: At least 717 people have been crushed to death in a stampede outside Mecca and more than 850 injured in the deadliest disaster on the annual hajj pilgrimage in a quarter of a century.

Panic broke out when two groups of pilgrims preparing for one of the last major rites of their trip collided at the intersection of two narrow streets. Within minutes the tarmac was a macabre jumble of dishevelled, partially clothed bodies.

The disaster revived questions about Saudi Arabia’s ability to manage the world’s largest annual migration, and the tragedy turned political as officials and diplomats began trading recriminations even before rescue operations had wound up.

The Saudi monarch, King Salman, ordered a review of the kingdom’s plans for the hajj after the disaster. Speaking in a live speech broadcast by Saudi-owned al-Arabiya television, he also said he had asked for a swift investigation into what he described as a painful incident.

Tehran accused Riyadh of failing its pilgrims after it emerged that dozens of the dead were Iranian, while some Saudi politicians appeared to push blame on to the dead themselves, with one reportedly making racist comments about African pilgrims.

The scale of the disaster was so vast that rescue teams worked into the evening to evacuate the injured and bodies of the dead, while security forces kept order among the thousands of pilgrims still filing through the area to finish their rituals.

Survivors described losing their loved ones and their clothes, in a frantic scrabble to escape the deadly crush as it surged down a narrow street with no exits. The toll may rise further, Al-Arabiya television channel quoted the interior ministry saying.

 “I saw someone trip over someone in a wheelchair and several people tripping over him. People were climbing over one another just to breathe,” said one of the survivors, 44-year-old Egyptian Abdullah Lotfy.

“It was like a wave. You go forward and suddenly you go back,” he told the Associated Press. Other survivors recounted being turned back from the entrance to tented camp areas as the crowd surged behind them.

“I saw the pilgrims were falling down and getting crushed and heard women and elderly people were screaming, asking for help,” said one survivor, who gave his name as Dr Abdul Rahman. “I tried very hard to get out, I lost all my clothes, they were torn off but I didn’t care and I managed to get out”.

“Then I tried to get in one of the tented camps but I was blocked by the security forces who kept preventing anyone from entering, and that doubled the crisis.”

Abdul Rahman eventually collapsed into a camp area when a security guard was distracted, and resisted attempts to throw him back out. But he said authorities were slow to arrive to calm the chaos. “I saw the civil defence there but they were very late,” he said. “I realised that there was a shortage of emergency exits, because there supposed to be ways of getting off a road every 50 metres.”

The tragedy came just weeks after a crane collapse killed more than 100 people and injured more than 200 more in the same area, and two hotels had to evacuate thousands of guests when major fires broke out, also injuring some pilgrims.

The string of major accidents has revived concerns about management of the hajj pilgrimage, which brings more than 2 million people to the holiest sites in Islam each year. Thousands of visitors have died in fires, stampedes and other disasters in recent decades.

Saudi Arabia’s king is also known as the Custodian of the two Mosques, an acknowledgement of his role protecting pilgrims and the sites they visit.

The Saudi health minister, Khalid al-Falih, pointed a finger of blame at the dead themselves, saying the pilgrims had been undisciplined.

“The accident, as most know, was a stampede caused by overcrowding, and also caused by some of the pilgrims not following the movement instructions of the security and hajj ministry,” he told a local TV channel.

High temperatures and exhaustion among may have contributed to the disaster, military spokesman Maj Gen Mansour al-Turki said, but he added there was no indication authorities are to blame. “Unfortunately, these incidents happen in a moment,” the Associated Press quoted him as saying.

Prince Khaled al-Faisal, head of Saudi Arabia’s central hajj committee, drew criticism on social media after reportedly blaming the fatal crush on “some pilgrims with African nationalities”.

Furious officials in Tehran accused local authorities of poor management of pilgrims in an area notorious for overcrowding, after it emerged that as many as 90 of the dead, or one in 10, may be Iranian. “Saudi Arabia’s officials are to blame for the incident,” said Amir Abdollahian, Iran’s deputy foreign minister for Arab and African affairs. He has summoned the Saudi envoy in Tehran over the deaths.

The two countries are old enemies, whose mutual distrust is amplified by sectarian differences. They have vied for regional influence for decades and are backing opposite sides in the wars in Yemen and Syria. (With inputs from Agencies)