The Syrian army on Thursday intensified its bombardment of a besieged camp for Palestinian refugees and nearby rebel-held areas in southern Damascus, the last area near the capital outside government control.

Most civilians have long since fled the Yarmouk camp, once the largest in Syria for Palestinian refugees, but enough have stayed behind that the United Nations has called on the warring parties to spare civilians.

The Russian-backed Syrian army launched a major offensive last week to capture the south Damascus enclave that includes Yarmouk and neighboring areas, which have been held for years by rebel fighters and Islamic State militants.