UN rights monitors have called for the global community to take urgent action to avoid a potential genocide against the Yazidi community in Iraq.
Thousands of members of the Yazidi religious minority are trapped on a mountain in northwestern Iraq with little food or water after Islamic State jihadists overran the region.
"All possible measures must be taken urgently to avoid a mass atrocity and potential genocide within days or hours," said UN minority rights expert Rita Izsak on Tuesday.
"Civilians need to be protected on the ground and escorted out of situations of extreme peril," Izsak said in a joint statement with fellow monitors, urging action by the Iraqi government and international community.
The refugees are stranded on Mount Sinjar, besieged by Sunni extremists from the Islamic State who control much of northern Iraq and eastern Syria.
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"We are witnessing a tragedy of huge proportions unfolding, in which thousands of people are at immediate risk of death by violence or by hunger and thirst," said Chaloka Beyani, UN monitor on refugee rights.
"Humanitarian aid must be delivered quickly and no efforts should be spared to protect all groups forcefully displaced by this conflict."
World Health Organization spokesman Paul Garwood said two medical teams had reached the mountain, while supplies had been sent in by helicopter.
The United States and France have also dropped aid supplies.
Some 35,000 people have managed to flee the mountain, head into Syria and then reach Iraqi Kurdistan.
Islamic State fighters have presented non-Muslims with a "convert or die" option, said Christof Heyns, UN expert on arbitrary executions.
"We cannot stand by in the face of such atrocities. International actors must do all in their power to support those on the ground with the capacity to protect lives," he said.
