NEW : Muslims are also attacked in the Shiite heartland . Three bombs explode in Kuwait City . Two more explode in northern Kuwait Shiite area . Fighting continues over Sunni - Shiite sectarian violence .
NEW : Pilgrims are also targeted in the Shiite heartland . Three bombs explode in Sadr City . Two more explode in northern Baghdad Shiite area . Fears intensify over Sunni-Shiite sectarian violence .