Fourteen of the missing have been found alive and seven bodies were in the morgue, it said.
The government has said 67 people were killed after al-Shabab militants stormed the Westgate centre in the capital, Nairobi, on 21 September.
MPs have started a probe into alleged intelligence failings over the attack.
The Red Cross says some relatives were not updating them when they found people who had been reported as missing.
A Red Cross tracing manager has told the BBC that “some were reports from people who could not get through to their relatives on the phone and thought they might have been at the mall”.
Source: BBC
