Red Cross official Titus Mong'oi on the continuing rescue effort
Rescue efforts are continuing to save about 20 builders trapped after a multi-story building collapsed on the outskirts of Kenya's capital, Nairobi.
At least seven bodies have been pulled from the wreckage in Kiambu town, where the building was under construction.
The Red Cross told the BBC 18 people had been rescued and taken to hospital.
It is not clear what caused the collapse, but correspondents say Kenyan building companies are often criticised for flouting safety regulations.
Relatives of people feared trapped have gone to the site hoping to see their loved ones pulled out alive.
Titus Munguo of the Kenyan Red Cross society told the BBC's Focus on Africa programme that time was running out for people to be saved.
"If one more night is taken, we can only rescue bodies, not somebody alive."
Up to 50 workers were believed to have been on site at the time of the collapse.
Some of those trapped have made mobile phone calls to alert relatives.
The incident is not the first building collapse in Nairobi
A reporter for the Associated Press news agency said he saw a woman's body in the wreckage, while one rescued man told AP several people had been in the room with him when the building collapsed.
There have been suggestions that recent heavy rain in the area could have weakened the five-storey structure.
Kenya's architecture association last week issued a report, saying that 65% of the country's buildings do not meet the required standards.
One eyewitness reported hearing a loud bang when the building cracked before it collapsed.
The BBC's Will Ross in Nairobi says the incident was not the first of its kind in recent years.
Following the collapse of other buildings, there were calls for stricter building regulations to be enforced, says our correspondent.
But Nairobi is currently experiencing a construction boom, and companies are often criticised for cutting corners and failing to enforce strict safety measures as profitable high rises spring up over the city, he adds.
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