At least 362 Hajj pilgrims were killed in a stampede in Mina as they sought to complete a farewell stone-throwing ritual before sunset.
The death toll from the stampede was the highest since 1990
The BBC's Aleem Maqbool in Mecca was on the Jamarat Bridge in Mina when the stampede happened. He described his experiences to the BBC's Today Programme.
I was in another part of the crowd to the stampede. It was very difficult then to be able to see what was going on in the area around you.
But it was straight after lunchtime prayers, which is when this ritual begins and we were right in amongst the pilgrims who were heading to these three pillars which form part of this final day ritual where each of the pilgrims have to stone these three pillars.
It was, to be quite frank, a very frightening experience. The crowd was coming towards the pillars from every direction and then forcing their way back out again.
There really wasn't any way of controlling which way we could go and so there was no surprise that there was trouble there.
We decided after just a couple of minutes of being there that we needed to get out because there was a serious risk of something happening.
Indeed, it turns out, at the very same time we were in the crowd, just about 200m away, this tragedy was unfolding.
All week the Saudi authorities have been assuring us that something like this would not happen.
There have been massive stampedes in the past. Just two years ago 251 people died and in 1990 over a thousand died.
They assured us this wouldn't happen.
What they have done that did work was to extend the pillars. They are now virtually walls, so there is more of an area for people to congregate around.
The pillars represent the spot where the devil appeared to Abraham
What they didn't do was to restrict the flow of pilgrims coming into the area and then regulate the flow within the area, because pilgrims have to go from one pillar to the next and then the third, and then leave the area.
But it has to be said that there was - this has been the government's line, and the King's line this morning - a lot of irresponsible behaviour by some of the pilgrims.
There were, for example, some pilgrims linking arms, barging towards the pillars and barging back out again.
But the point that the government is stressing is that, against official wishes, a lot of pilgrims brought with them all of their luggage and they say it was this particular point that caused the stampede.
There were a lot of people with heavy luggage. Once one person trips over, then with the flow of people behind them...
You have to remember, an estimated three million people were piling into this area at the same time.