Amani National Congress (ANC) party leader has expressed his message of goodwill to the families and victims of the Riverside attack.
In a tweet, Mudavadi noted that his son was at the premise but was rescued by the multi-agency security team leading the operation.
He applauded the security forces for responding swiftly and running a properly coordinated rescue mission.
"I’m deeply shocked & saddened by the cowardly terrorist attack. As my prayers go out to the casualties & their families, I commend the security forces for their swift & coordinated action. My son was among those rescued and we are grateful to all who called expressing their concern," he tweeted.
He urged Kenyans to rally behind state agencies in the rescue mission.
Elsewhere, the daughter of former Kakamega Senator Boniface Khalwale was also trapped in the attack.
She was, however, rescued on Wednesday morning by the security forces coordinating the mission.
"3:27 am and my Zinzi is evacuated! I thank Mr Kanja (GSU Commandant) the rescue operations commander, Mike Lekaleile (OCS Muthangari) and the rest of the security forces for saving the hostages. Islamic fundamentalism has no place in the modern world and must be defeated," he tweeted.
Here is Mudavadi's full statement: