Two people have been pulled alive from the rubble of a building that collapsed in Kenya's capital, Nairobi, on Friday, as a search continues for five still missing.

Police said on Saturday that a manhunt had been launched for the building's owner and the contractor responsible for the site.

Dramatic footage shows the bottom floor of the block, thought to have been 16 or 18 storeys, giving way before the rest of the building crumples, sending a plume of dust into the surrounding streets.

Dozens of builders had been working on the upper floors when it collapsed, but managed to emerge largely unscathed. Those missing were thought to have been in shops at the base of the building.

The incident has raised fresh concerns about construction standards and regulations in Kenya.

The block was under construction when it collapsed on Friday afternoon, with footage showing scaffolding still wrapped around the outside of the building. Officials said 11 shops had already opened on the bottom floors.

Interior ministry official Kipchumba Murkomen said 66 of the 67 construction workers in the building at the time had been able to get out unharmed, while the other had suffered injuries that were not life-threatening.

On Friday, Murkomen said that seven people had been reported missing and rescue teams had made contact with some of those trapped beneath the rubble.

The two survivors rescued on Saturday have been taken to hospital, police said.

Images from the scene, in Nairobi's Eastleigh area, show the concrete floors of the building piled on top of one another, as rescue workers saw through metal to get to those believed to have been stuck underneath.