With an unknown number of people still trapped under the rubble of an unfinished office building, and 11 known dead, search crews scoured the wreckage in downtown Nairobi for a second night.
They ripped up a tangled mass of concrete slabs, wire mesh and metal bars left by Monday's cave-in, which also injured more than 100.
Although buoyed by the rescue of the three survivors on Tuesday, including two in the pre-dawn hours and one pulled out nearly 24 hours after the building collapsed, hopes dimmed of finding any more than a few left alive as the hours passed and the death toll rose.
"Now, we have 11 dead," national police spokesman Jaspher Ombati said. "We shall not give up, we will continue with the search well into the night and tomorrow."
Assisted by a 140-strong Israeli military search and rescue unit, a team of US naval engineers and paramedics from a base in Djibouti and a small number of British experts, Kenyan crews kept up the painstaking work as the east African nation, already in the throes of a drought disaster, was gripped by the crisis.
Rescue broadcast live
Television audiences sat transfixed before non-stop live coverage on all local broadcast networks of workers with jackhammers and power saws assailing concrete and mortar, trying to reach those still buried.
Amid the cacophony of shouting, power tools and heavy machinery, TV viewers and radio listeners hung on the words of the reports, particularly when it was announced that contact had been made with six survivors who were receiving oxygen and glucose through cracks in the debris.
Not long afterward, as the tragedy neared its 24-hour mark, Israeli and Kenyan rescuers hoisted one of the six, Martin Muya, from the rubble alive, on a stretcher with an intravenous tube in his arm, to loud applause from onlookers.
But a few hours later, officials said another of the six, a man trapped near Muya, had died, and that voice contact had been lost with all but one of the others, although sniffer dogs had located live humans in three other areas.
"There is still hope that we can rescue some people alive," said Brigadier General Emilio Tanui, who was supervising the operation for the Kenyan military.
Official spokesmen said that in addition to the 11 confirmed dead, at least 106 people had been injured, many seriously when the the building collapsed on Monday around 2:30 pm (1130 GMT).
They dismissed claims by Kenyan emergency workers that the death toll was actually hovering around 20, but Mr Ombati said: "I have to emphasize that this is not the final toll."
President tours site
President Mwai Kibaki, who cut short an official visit to Sudan for a summit of African Union leaders because of the disaster, toured the site and vowed to improve Kenya's disaster response capacity, which has been roundly criticised.
Deputy public works minister Joshua Toro said that initial findings of a probe into the collapse found that the responsibility for the collapse lay with the contractor and perhaps the city council.
"There is a problem in the engineering design," he said. "We have established that there was no structural engineer involved here."