NAIROBI, Kenya — Rescuers found four survivors Thursday in the rubble of an apartment building that collapsed six days ago amid heavy rains in the Kenyan capital, raising hopes that more people might still be alive in a disaster that has left dozens dead and missing.

The first to be rescued was a pregnant woman, although her husband said that amid the joy of finding her alive, doctors also reported that their baby had not survived. In addition, one of those found alive later died en route to the hospital, officials said.

Soldiers, firefighters and volunteers have been working around the clock since the April 29 collapse of the seven-story building in a desperate search effort, and their spirits were lifted Tuesday when a nearly 6-month-old girl — dehydrated but relatively unscathed — was found in a wash basin.

Then on Thursday, they found 24-year-old Elizabeth Night Odhiambo, who was eight months pregnant, said her husband, Stephen Onyango.

A crowd broke into applause as Odhiambo — under a blanket and with her face covered with an oxygen mask — was carried to an ambulance in a scene broadcast live on Kenyan TV.

Odhiambo was taken to Kenyatta National Hospital, where she underwent an emergency cesarean section, but doctors told Onyango the baby had not survived.

“A doctor pulled me aside and told me, ‘Your wife is here in the (operating) theater, and when she was in the collapsed building, the baby died in her stomach and we have removed it,’” Onyango told The Associated Press. “He showed me the baby, and I told him it was OK.”

Despite that news, Onyango said he was joyful his wife was still alive.

“I cannot say the happiness I have,” the truck driver said in a telephone interview. “I have never had such happiness like this in my life.”

Onyango said he was able to comfort his wife after the surgery.

Pius Masai, the head of the Disaster Management Unit, said that of the other three people rescued after Odhiambo, one died because the ambulance did not have advanced life-saving equipment. The condition of the other two was not immediately known.