The attack claimed by Somali militant group al-Shabab killed at least 61 civilians, six security officers and five extremists, the president said.
Another 175 people were injured, including more than 60 who remain hospitalized.
Fears persisted that some of the attackers could still be alive and loose inside the rubble of the mall, a vast complex that had shops for retailers like Bose, Nike and Adidas, as well as banks, restaurants and a casino.
A high-ranking security official involved in the investigations said it would take time to search the whole mall before declaring that the terrorist threat had been crushed. That official insisted on anonymity in order to discuss information not publicly disclosed.