The UN has called for action to prevent what it says may be a possible massacre in the northern Iraqi town of Amerli.
Special representative Nickolay Mladenov says he is "seriously alarmed" by reports regarding the conditions in which the town's residents live.
The town, which has been besieged by Islamic State for two months, has no electricity or drinking water, and is running out food and medical supplies.
The majority of its residents are Turkmen Shia, seen as apostates by IS.
"The situation of the people in Amerli is desperate and demands immediate action to prevent the possible massacre of its citizens," Mladenov said in a statement.
"I urge the Iraqi government to do all it can to relieve the siege and to ensure that the residents receive life-saving humanitarian assistance or are evacuated in a dignified manner."
Residents say they have had to organise their own resistance to the militants and no foreign aid has reached the town since the siege began.