More than 700 people were crushed to death Thursday near Mecca, Saudi Arabia, in a stampede.
More than 800 others were injured. The victims were part of the Muslim Hajj pilgrimage, which began Tuesday.
Saudi officials say the stampede happened in Mina, about five kilometers from Mecca. Hajj pilgrims go to Mina to throw rocks at three stone walls that represent evil. It is the final part of the Hajj ritual before the yearly Eid al-Adha religious observance. The pilgrims also spend the night at Mina. The area has more than 160,000 tents for the visitors.
The Saudi Arabian civil defense department reported the number of dead and injured on the social media website Twitter.
There have been several deadly stampedes at the Hajj during the past 25 years. Huge numbers of people gather for the five-day-long event. This year, 2 million pilgrims are taking part. All Muslims are required to go on the Hajj at least once, if they are able.
Last year, Saudi Arabia reduced the number of pilgrims because of concerns about safety.
The worst Hajj stampede happened 25 years ago inside a tunnel in Mina. More than 1,400 people were killed. Stampedes in three other years -- 1994, 2004 and 2006 -- each killed more than 200 people.
Earlier this month, a construction crane collapsed during Friday prayers at the Grand Mosque in Mecca. Workers had been expanding the mosque. More than 100 people were killed and more than 200 others injured. Officials said high winds during a rainstorm caused the crane to collapse. The machine had reportedly been operating at the construction project for three or four years.
The Grand Mosque is Islam's holiest site. It is among the largest religious centers in the world and has millions of visitors every year.
I'm Christopher Jones-Cruise.