The UN secretary-general says the Yarmouk Palestinian refugee camp near Damascus that has been overrun by Islamic State group fighters is "the deepest circle of hell" in Syria's four-year horror.
Ban Ki-moon told reporters Thursday that "a refugee camp is beginning to resemble a death camp" for its estimated 18,000 residents.
He warns that the armed fighters inside the camp and Syrian government forces outside it are a double-edged sword for the thousands trapped.
"We simply cannot stand by and watch a massacre unfold," Ban says.
Islamic State group fighters overran much of the Yarmouk camp last week.
The secretary-general is demanding an end to the fighting, access for humanitarian aid and safe passage for people who wish to flee.
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