In Saudi Arabia, 717 people have been killed in a stampede near the holy city of Mecca on Thursday morning.

BBC reports pilgrims were taking part in the hajj, the holy pilgrimage Muslims attend, when a stampede broke out, killing 717 people. An additional 863 people were injured during the incident. Among those who were killed were 43 Iranians.

The stampede occurred Thursday morning, during the ritual known as "stoning the devil" in the tent city of Mina, about 2 miles from Mecca, Islam's holiest city. According to Muslim tradition, pilgrims throw stones at three pillars in a reenactment of when the Prophet Abraham stoned the devil and rejected his temptations.

The hajj began earlier this week and culminates with Eid al-Adha, or the Feast of Sacrifice, which began Thursday.

It is the deadliest accident during the hajj since 1990, when 1,426 pilgrims died in a stampede in a tunnel linking Mecca and Mina.

According to the Los Angeles Times, the hajj pilgrimage is one of the five pillars of Islam, and many Muslims believe they should perform the hajj at least once in their lives. It drew 2 million Muslims to the area this year.

Saudi officials believe that the incident started when there was a "sudden increase" of pilgrims heading toward the pillars. The commotion resulted in a stampede in which a large number of pilgrims fell to the ground. The Saudi crown prince held an emergency meeting and ordered an investigation into the stampede.

Many people took to Twitter to give their perspectives on the incident, tweeting out photos and videos of the incident. You can check some of those out below:

This is the second deadly incident to occur during the hajj this year. Just 13 days ago, a crane collapsed, killing more than 100 people at the Grand Mosque in Mecca.