Rescuers in the Kenyan capital Nairobi are searching for dozens of people feared trapped after the collapse of a six-storey building in heavy rain.

TV coverage from the scene showed a crowd gathering at the Huruma residential estate as rescuers dug for survivors. At least three people are known to have died.

The Red Cross criticised "chaotic scenes" as rescuers arrived.

It is unclear how many people are trapped beneath six floors of concrete.

The rainfall in addition has caused landslides, washed away houses and flooded roads.

The Huruma neighbourhood is a poor district on the outskirts of Nairobi made up of narrow streets, meaning firefighters struggled to get to the scene and were delayed by large crowds.

After some time, the army took charge of the rescue - with the help of the Kenyan Red Cross.

"We can still hear voices of people who are still inside," Red Cross spokesman Venant Ndigila said.

"[So far] we [have] managed again to rescue at least 12 people - and there are signs that there are still some people who are still alive."

Residents said that the building shook violently in the rain before collapsing.

Poor building standards are a fact of life in Kenya, correspondents say. A survey carried out last year found that more than half the buildings in the capital were unfit for habitation.

The high demand for housing in Nairobi has led to some property developers bypassing building regulations to reduce costs and increase profits.

There has however been some good news for the rescuers who extracted a number of children from the wreckage throughout Friday.

President Uhuru Kenyatta last year ordered an audit of all the buildings in the country after a spate of collapses.

Meanwhile two boys are missing in another part of the flood-hit country after going herding, according to the Red Cross.