Officials said the death toll could rise by a further 60 as more bodies are found in the rubble of the Nairobi mall, where three floors collapsed.
The attack, which began on Saturday when al-Shabab extremists stormed the Westgate shopping centre, has already claimed more than 60 civilian lives, with at least six Britons dead.
Yesterday experts from countries including the UK, the US and Israel were working with Kenyan authorities on the forensic investigation into the Nairobi mall massacre.
Explosives experts and sniffer dogs were searching for booby traps in the wreckage and sporadic gunfire was heard as teams moved through the mall.
The Foreign Office confirmed that a Briton had been detained in the Kenyan capital but could not say if the detention was being linked to the mall shootings, or give details of when and where the person was held.
It has been reported that the Briton was a 35-year-old man, believed to be of Somalian origin, who was detained at Jomo Kenyatta airport on Monday afternoon.
The crisis began on Saturday when 10 to 15 al-Shabab extremists stormed the mall, throwing grenades and firing on terrified shoppers.
The terrorists roamed through the complex reportedly seeking to separate Muslims - who were allowed to leave - from non-Muslims, who were killed or taken hostage.
Scotland Yard has said a team of officers has travelled to Nairobi to help with "post incident procedures".