Authorities in Saudi Arabia say at least 717 people have been killed in a crush at Mina, outside the holy city of Mecca, where two million people are performing the annual hajj pilgrimage, the Guardian reports.

Hundreds more were injured, civil defense officials said.

There have been stampedes during the hajj on at least six previous occasions, killing hundreds of pilgrims. In 1990, more than 1,400 died in a stampede inside a tunnel.

It is a religious duty for able-bodied Muslims to complete the hajj – one of the five pillars of Islam – at least once. The rituals involved in the pilgrimage are intended to cleanse the soul and promote the bonds of brotherhood and sisterhood within Islam.

Pilgrims this year have been undeterred by the collapse of a construction crane in Mecca earlier this month, which killed more than 100 people and injured at least 200. An investigation has been launched into the cause of the collapse amid claims the proper safeguards are ignored in the race to complete developments surrounding the Grand Mosque. Among the projects under construction is a 10,000-bed hotel.

Last week, more than 1,000 pilgrims were evacuated from a hotel in Mecca in the early hours of the morning after a fire broke out.

The latest deaths are likely to raise questions about Saudi authorities handling of safety during the hajj pilgrimage, when 2-3 million people travel to Mecca.

Pilgrims continued to arrive at the site despite the stampede. “Work is under way to separate large groups of people and direct pilgrims to alternative routes,” the Saudi civil defence directorate said.

The hajj pilgrimage is one of the five pillars of Islam, and it is a religious duty for able-bodied Muslims to make the journey at least once in their lives.