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.
Foreign Secretary Philip Hammond has expressed sadness at the "enormous loss of life in Mecca" after hundreds were killed in a crush during the Hajj pilgrimage.
It is currently unclear whether any Britons were among those killed and injured, and Hammond said Foreign Office staff were "in close contact with the Saudi authorities and tour operators, and are checking hospitals and other locations to urgently gather information about British nationals who may require assistance."
"We are also deploying further staff from the region to bolster our response," he said.
Anyone concerned about British nationals attending the pilgrimage is advised to telephone the embassy in Riyadh or tweet the FCO Twitter account.
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.