At least 13 people have been killed and dozens more wounded in an attack by gunmen on a shopping mall in Nairobi, Kenyan police said. \"At the rear of the mall, there are 13 bodies in different places. My colleagues who were on the upper floors say there are more bodies, but I have seen 13,\" a police senior official told AFP at the scene. The Kenyan Red Cross said dozens of people had been wounded and issued an appeal for blood donations.