The death toll following a crush at the annual Hajj pilgrimage in Saudi Arabia is now 769 and the number of injured has risen to 934.
Witnesses claimed police had closed entrances and exits to the pilgrims' camp, making the disaster inevitable, while Iran's Supreme Leader accused authorities of "mismanagement".
King Salman has ordered an immediate review into safety procedures.
Hundreds Iranians have gathered in the city's capital shouting "death to the Saudi dynasty!" following yesterday's disaster near Mecca.
At least 131 Iranian nationals are now thought to have died in the crush during the Hajj pilgrimage, and politicians in Tehran have pointed the finger of blame squarely at Saudi authorities.
The anger follows comments by the Saudi health minister which appeared to deflect blame for the disaster on to those that died.
Khalid al-Falih said: "The investigations into the incident of the stampede that took place today in Mina, which was perhaps because some pilgrims moved without following instructions by the relevant authorities, will be fast and will be announced as has happened in other incidents."
The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.