Aid delivery teams for the United Nations were “ready to roll” if a humanitarian pause could be enforced, Mr. O’Brien said, but for now it was too dangerous “even for the very brave people on the ground — they are brave, but they are not suicidal.”
Hundreds of thousands of people have been killed in Syria and millions displaced since the conflict began in March 2011 as a peaceful opposition movement against President Bashar al-Assad. The Syrian Center for Policy Research, a Damascus-based group, estimated earlier this year that the death toll was at least 470,000.