Kenya's interior minister said on Wednesday that only an "insignificant" number of bodies were thought to remain in the wreckage of Nairobi's Westgate mall.
Countries including Britain, the United States, Israel, Germany and Canada are assisting the probe into the four-day siege by
Islamist gunmen, which left 67 dead and dozens more missing, Joseph Ole Lenku told reporters.
"We strongly believe... that there are insignificant numbers of bodies still holed up," the minister said, playing down fears that the bodies of 71 people listed as missing by the Red Cross may still be inside.
President Uhuru Kenyatta announced an end to the 80-hour bloodbath late on Tuesday, with the "immense" loss of 61 civilians and six members of the security forces. Police said the death toll was provisional.
"It is an elaborate process. Among the things that are going on now are fingerprinting, DNA identification (and) ballistic examinations," Lenku said of the probe, adding that the evidence collection would take at least a week.
"We expect the exercise of the forensic audit will take not less than seven days, but for the exact results coming out of that, we leave for the experts to determine."
He also said he could not comment on media reports that the attackers had rented a shop inside the mall before the attack.
"We are getting a lot of information, and suggestions and input from people of good will, also from rumourmongers," he said. "As for whether they had a shop in the mall, it is something that we cannot categorically give you a position on."