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.
A senior British Muslim has called on the government to put pressure on Saudi authorities over a crush that killed at least 719 people and injured 863 during the Hajj pilgrimage.
Khalid Anis, an executive on the board of the Islamic Society of Britain, said it was a tragedy that "people are allowed to die on something which should be spiritual and peaceful".
"Obviously we all want answers. We all need to know why this happened. There just needs to be a clear, transparent analysis of what went wrong," he said.
He said the British government should "push the Saudis" to hold an "open" inquiry into the disaster.
However, he added: "Am I confident that it will be looked at and analysed properly? No. Because it's already turned into a blame game and we have no idea of the story."
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.