The owner of a building which collapsed in Kenya's capital Nairobi on Friday, killing at least 21 people, has been arrested, police have told the BBC.

Samuel Karanja Kamau would appear in court on Tuesday, police added.

Earlier, officials said he did not have permission to rent out 119 rooms in the six-storey building. Mr Kamau has not yet commented on the allegation.

More than 90 people are still feared trapped beneath the rubble, reports the BBC's Abdinoor Aden from the scene.

Rescue operations are continuing, he adds.

About 135 people have been freed so far from the collapsed building, local media reports.

The governor of Nairobi, Evans Kidero, said that officials who approved the construction of the building in the poor neighbourhood of Huruma would be sacked.

Three days of rainfall caused landslides and flooded roads in Nairobi.

More than 800 homes were affected by the flooding, Kenya's Red Cross said.

It criticised "chaotic scenes" as rescuers arrived after the Friday night collapse.

Nairobi's police chief has said rescue teams were delayed on their way to the scene by hours-long traffic jams caused by flooded roads.

Huruma is made up of narrow streets, and this made it more difficult for rescue workers to reach the scene, local media reports.