UPDATE Deadliest Hajj Stampede in 25 Years: At Least 717 Killed In Saudi Arabia

At least 717 people taking part in the Hajj pilgrimage have been killed in a stampede near the Islamic holy city of Mecca, officials in Saudi Arabia say. Another 863 people were injured in the incident at Mina, which occurred as two million pilgrims were taking part in the Hajj's last major rite.

There were people from Nigeria, Niger, Chad and Senegal among other nationalities.

It is the deadliest incident to occur during the Hajj in 25 years.

BBC report continues:

Preparations for the Hajj were marred when a crane collapsed at Mecca's Grand Mosque this month, killing 109 people.

Pilgrims travel to Mina, a large valley about 5km (3 miles) from Mecca, during the Hajj to throw seven stones at pillars called Jamarat, which represent the devil.

The pillars stand at three spots where Satan is believed to have tempted the Prophet Abraham.

People were going towards the direction of throwing the stones while others were coming from the opposite direction. Then it became chaotic and suddenly people started going down.

There were people from Nigeria, Niger, Chad and Senegal among other nationalities. People were just climbing on top of others in order to move to a safer place and that's how some people died.

People were chanting Allah's name while others were crying, including children and infants. People fell on the ground seeking help but there was no-one to give them a helping hand. Everybody seemed to be on their own.

It affected some members of our group. I lost my aunt as a result of the stampede and at the moment, two women from our entourage - a mother and her daughter - are still missing.

The Saudi civil defence directorate said in a statement that the stampede occurred at around 09:00 local time (06:00 GMT) at the junction of Street 204 and Street 223.

The pilgrims were walking towards the five-storey structure which surrounds the pillars, known as the Jamarat Bridge.

The incident happened when there was a "sudden increase" in the number of pilgrims heading towards the pillars, the statement said.

Security personnel and the Saudi Red Crescent were "immediately" deployed to prevent more people heading towards the area, the directorate said.

Photographs showed the bodies of dozens of pilgrims on the ground, some piled high. They were all dressed in the simple white garments worn during the Hajj.

The civil defence directorate said the victims were of "different nationalities", without providing details.

As well as victims from Niger witnessed by the BBC's correspondent at the scene, Iran's state news agency, Irna, said at least 47 Iranians were among the dead.

Hajj: Previous tragedies

• 2006: 364 pilgrims die in a crush at foot of Jamarat Bridge in Mina

• 1997: 340 pilgrims are killed when fire fuelled by high winds sweeps through Mina's tent city

• 1994: 270 pilgrims die in a stampede during the stoning ritual

• 1990: 1,426 pilgrims, mainly Asian, die in a stampede in an overcrowded tunnel leading to holy sites

• 1987: 402 people die when security forces break up an anti-US demonstration by Iranian pilgrims

The wounded were taken to four hospitals by more than 220 rescue vehicles.

Saudi Crown Prince Mohammed bin Nayef, who headed an emergency meeting after the stampede, has ordered an investigation.

The Saudi health minister, Khaled al-Falih, said the crush occurred because many pilgrims moved "without respecting the timetables" established by authorities.

Image copyright AP Image caption Pilgrims converge on Mina to cast stones at three pillars representing the devil

Saudi-owned al-Arabiya TV reported that the head of the central Hajj committee, Prince Khaled al-Faisal, had blamed the stampede on "some pilgrims with African nationalities".

But the head of Iran's Hajj organization, Said Ohadi, told Irna that two paths close to the scene of the incident had been inexplicably closed off by the Saudi authorities, resulting in the build-up in pilgrims.

The UK Foreign Office said it was in contact with the local authorities and was urgently seeking more information about whether British nationals were involved.

What happens at the Hajj?

What rituals do pilgrims perform? The pilgrimage takes place in several stages over five days, including circling the Kaaba (a cube-like building in the centre of Mecca's Grand Mosque) en masse and throwing seven stones at pillars called Jamarat which represent the devil.

How many people go? Well over a million pilgrims from outside Saudi Arabia, and several hundred thousand from inside the kingdom, converge on the site each year.

How do the authorities cope? Authorities deployed 100,000 security personnel and 25,000 extra health workers this year, as well as 100,000 air-conditioned tents for temporary accommodation.

The Saudi authorities have spent billions of dollars on improving transport and other infrastructure in the area in an attempt to try to prevent such incidents.

The Hajj is the fifth and final pillar of Islam. It is the journey that every able-bodied adult Muslim must undertake at least once in their lives if they can afford it.

The number of people attending Hajj rose from 57,000 in 1921 to a high of 3.2m three years ago, according to the Saudi Central Department of Statistics and Information.

That figure dropped to just over two million last year.