More than 700 people have been killed and 805 people injured in a violent stampede Thursday at the holy hajj pilgrimage in Saudi Arabia. Officials initially said 450 people had been killed, but the death toll quickly climbed to 717 victims, CNN reported.

The stampede unfolded during a ritual known as "stoning the devil" in the tent city of Mina, located 2 miles from Mecca, Islam's holiest city. Crowds of pilgrims throw stones at three pillars during the ritual to remember when the Prophet Abraham rejected the devil, according to Muslim tradition. But a surge in the crowd caused some people to fall, prompting the deadly stampede.

Hajj pilgrims from different countries were reported to have died, including several dozen from Iran. More than 220 ambulances and 4,000 rescue workers responded to the stampede. "We have a stampede accident in Mina, and civil defense is dealing with it," said Brig. Gen. Mansour al-Turki, an Interior Ministry spokesman.

The head of Iran’s hajj organization, Said Ohadi, blamed poor planning from Saudi Arabia for the deaths. “Today’s incident shows mismanagement and lack of serious attention to the safety of pilgrims. There is no other explanation. The Saudi officials should be held accountable," he said.

Ethar El-Katatney, a pilgrim who was near the stampede site, told CNN she walked past ambulances filled with bodies of victims. "I saw the ambulances, I saw bodies. ... At least 20, 30 ambulances passed me by," she said.

The annual Islamic pilgrimage to Mecca has seen violent deaths in previous years and earlier this month a crane collapse killed more than 100 people at another major Islamic holy site, the Grand Mosque in Mecca. In 2006, a stampede claimed 363 lives.

Thursday was the third day of the hajj. The pilgrimage is conducted over five days.

Videos of the hajj stampede can be seen below:

Pictures of the stampede are below: