Emmanuel Chirchir told Capital News FM of Nairobi that among the areas they intend to hit are Baidoa, Baadheere, Baydhabo, Dinsur, Afgooye and the port city of Kismayu.
He said Kenya had received reliable information indicating al-Shabaab militants were regrouping in those regions and received a shipment of arms on Tuesday.
"In line with the Kenya Defense Forces strategy of diminishing al-Shabaab effectiveness and weapon use, the aforementioned towns will remain under imminent attack," Chirchir said. "Residents in the towns are advised to avoid contact with al-Shabaab militants."
The Somalia chief for the International Committee of the Red Cross urged all sides to respect civilian lives.
"All feasible precautions must be taken to avoid, and in any event to minimize, incident loss of civilian life, injury to civilians and damage to civilian objects," said Pascal Mauchle.