Syrian troops captured a rebel-held area on the edge of Aleppo on Saturday, tightening their siege on opposition-held neighborhoods in the northern city after what residents described as the heaviest air bombardment of the 5 1⁄2-year civil war. The UN meanwhile said that nearly 2 million people in Aleppo, Syria's largest city and onetime commercial center, are without running water following the escalation in fighting over the past few days. The UN Security Council called an emergency meeting for Sunday morning to discuss the escalating attacks. Government forces captured the rebel-held Palestinian refugee camp of Handarat as air strikes pounded rebel-held eastern neighborhoods of Aleppo, killing 52 people, including 11 children and six women, according to the Britain-based Syrian Observatory for Human Rights. The Local Coordination Committees, another monitoring group, said 49 were killed on Saturday alone. The Observatory said the death toll in Aleppo is expected to rise since many people are in critical condition and rescue workers are still digging through the rubble. Residents say the latest bombardment is the worst they've seen since rebels captured parts of the city in 2012. Activists reported dozens of air strikes on Friday alone. "Since the beginning of the crisis, Aleppo has not been subjected to such a vicious campaign," said Mohammed Abu Jaafar, a forensics expert based in the city. "Aleppo is being wiped out." For days, videos and photographs from eastern Aleppo have shown flattened buildings and paramedics pulling bodies from the rubble. Wounded people have flooded into clinics, where many are being treated on the floor because of a lack of stretchers. "People in Aleppo already suffocating under the effects of the siege, have yet again come under horrific attack," said Carlos Francisco of Doctors Without Borders, which supports a number of area clinics. "No aid, including urgent medical supplies, is allowed to enter." "We are deeply worried by the high numbers of wounded reported by the hospitals we support, and also know that in many areas the wounded and sick have nowhere to go at all — they are simply left to die." UN chief Ban Ki-moon condemned the "chilling" escalation in Aleppo, which he said marked the "most sustained and intense bombardment since the start of the Syrian conflict." The statement issued by his spokesman said the reported use of "indiscriminate" weapons in densely populated areas "may amount to war crimes." US Secretary of State John Kerry, speaking at Tufts University in Boston, said what was happening in Aleppo was "beyond the pale." — AP