Floodlights lit the 60-foot-high pile of rubble and metal that once was a three-story building, while Red Cross workers and soldiers crawled over it like ants, hammering feverishly with picks and shovels and stopping only once in a while to listen for signs of life: a muffled voice, a whimper or a cry.A crane donated by a local construction firm was being used to lift the heavy slabs from the top of the rubble mountain of the Ufundi Co-op Building. Bulldozers loaded up dump trucks, as crowds of people watched in dark silence from the blackened street.

Firefighters and welding teams climbed up the mass of broken concrete and tried to cut through the building's metal beams and twisted innards. The building was nearly leveled by the blast that devastated the rear of the U.S. Embassy next door.

There were a few moments of triumph. At 9 p.m., rescuers said, three people were found alive in a partially collapsed room. An hour later, another four were recovered from an elevator.

But there were far more moments of tragedy. Scores of people were found crushed under tons of concrete. The rescue workers fought off fatigue after more than 14 hours of laboring.

"My team has brought out more than 30," said Farid Abdul Kadir of the Kenyan Red Cross, as he came down for a break. "I have been the unluckiest. All of them have been dead."

Another volunteer, Caleb Kilande, 29, worked for four hours and found four people. Three had been crushed to death, their heads mashed beyond recognition. But the fourth, a man pinned under a slab of concrete, was still breathing.

"He was still conscious and breathing, the chest coming up, slowly, slowly, and his eyes were seeing," Kilande said. "It took us a long time to get him out because he was trapped under heavy slabs. It was almost an hour. I do not know if he will live."

Most of the workers are volunteers or members of the Kenyan armed forces. Many said they have had little training to prepare them for a disaster like this one. In fact, Kenya's emergency system has never seen a disaster on this scale before, they said.

Many wondered aloud how a violent act of this magnitude could be committed in their country, which is better known for wildlife and beaches than for terrorists.

As always in disasters like this one, the rescuers were racing against time. The building housed a secretarial school, as well as several businesses. No one knows how many people were inside when the bomb exploded at 10:35 a.m.

Arfan Tufail, a 30-year-old businessman who is part of the Citizens Neighborhood network, said he and his colleagues heard two voices earlier in the day coming from deep in the rubble.

After hours of work, however, the rescuers had still had not managed to reach the trapped people. The voices stopped, Tufail said. "We don't know if they are still alive."