Kenyan officials have released footage showing the devastation inside the Nairobi shopping centre after the terror attack.

Kenyan President Uhuru Kenyatta said that three floors in a part of the complex had collapsed near the end of the operation, leaving an unknown number of bodies under steel and concrete.

They are latest shocking pictures to emerge from inside the mall.

Yesterday, an amateur video captured the moment a courageous bystander led a mother and her two young children to safety.

The terrified family are 'playing dead' when the man, reportedly a police officer, intervenes and reassures them before helping the trio leave the building.

But stories of heroic rescues from the early hours of the attack have given way to those of families desperately searching for their missing loved ones.

As Kenya entered a three day period of national mourning, more questions are being raised about the government's response to the siege.

Three floors of the shopping centre collapsed during the assault. Credit: ITV News

A team of international forensic experts is currently helping search for evidence at the scene.

The floor inside the shopping centre is covered in debris. Credit: ITV News