United Nations officials in Iraq are warning that a massacre could take place in a town where thousands of members of the Shia Turkmen minority are besieged by Islamic State militants.
The UN special envoy to Iraq said up to 18000 residents are enduring unspeakable conditions in the town of Amerli which has been cut off from food and water for almost two months.
Only small amounts of aid have been delivered by Iraqi army helicopters.
The UN said it fears the jihadists could overrun the town as they have done elsewhere in Iraq, showing no mercy to those who deviate from their extremist interpretation of Islam.
A UN special representative, Nickolay Mladenov, said he is "seriously alarmed" by reports regarding the conditions in which the town's residents live.
The town, under siege by the Islamic State for two months, has no electricity or drinking water, and is running out of food and medical supplies.
The majority of its residents are Turkmen Shia, seen as apostates by IS.
The town's inhabitants say they have had to organise their own resistance to the militants and no foreign aid has reached the town since the siege began.
James Foley murder 'betrays Britain' - British Foreign Secretary
British Foreign Secretary Philip Hammond said the risk post by the Islamic State would persist for a generation.
Mr Hammond said the murder of a US journalist by an Islamic State militant believed to be from the UK is "an utter betrayal of everything the British people stand for."
More than 500 British citizens are thought to have travelled to Syria and Iraq to fight in the past few years.
Mr Hammond said the UK had assisted Kurdish Peshmerga fighters, who are battling against Islamic State, with military aircraft delivering equipment.
He confirmed Britain would soon start sending eastern European ammunition and weaponry "with which they are already familiar".
He also said the government was "scoping out" what the UK might supply itself - such as night vision equipment, weapons and ammunition - although no specific request had yet been made.