NEW : An Al-Shabaab commander says its militants will strike Kenyan targets in return . The group has been fighting for years to overthrow the government and establish an Islamic state across much of Somalia. Another Kenyan official said Al-Shabaab wants to talk . The United Nations estimates the group collects up to $ 50 million a year from businesses in Kismayo , about half of its annual income . Kenyan forces entered Somalia two weeks ago to pursue Al-Shabaab .
NEW : An Al-Shabaab commander says its militants will strike Kenyan targets in return . The group has been fighting for years to overthrow the government and establish an Islamic state across much of Somalia. Another Kenyan official said Al-Shabaab wants to talk . Kenyan forces entered Somalia two weeks ago to pursue Al-Shabaab .