SAVAR, Bangladesh — The mother stood at the edge of the wreckage, pressing her lips to photos of her two children — Asma, who had worked in a garment factory on the fourth floor, and Sultan, who worked on the fifth.

For five days after the building collapsed, rescue teams had retrieved corpses and survivors, but not her son and daughter. Tears on her cheeks, she began to shout: at a soldier sweating beneath a hard hat, at the shattered building, at her god, and finally at her children, calling out their names, beckoning to them, “Today, I’m here! But you haven’t come back!”

Thousands of people surrounded the site on Sunday, watching the huge rescue operation, even as hopes faded that many more victims would be found alive. For nearly 12 hours, rescuers tried to save a trapped woman, lowering dry food and juice to her as they carefully cut through the wreckage trying to reach her. But then a fire broke out, apparently killing the woman, leaving many firefighters in tears.