At least 310 people have been killed and over 450 injured in a stampede during the pilgrimage near the Islamic holy city of Mecca, BBC reports.

The tragedy occurred in the valley of Mina, 5 kilometers from Mecca visited by Hajj pilgrims to perform devil stoning ritual. Currently, the cause of the incident is still being investigated.

Each year, several million Muslims go on a pilgrimage to holy places. Mecca is the major holiest site to visit by pilgrims as it considered to be the birthplace of Muhammad and Islam. According to tradition, every able-bodied adult Muslim must undertake the Hajj at least once in their lives.