NEW : the Middle East congratulates Iraqi , mourns loss of life , praises overall security level . Polls close in Iraq ; results expected by Wednesday , U.N. says . `` It 's an opportunity we ca n't miss , '' dozens Iraqis voter says . Militants carry out attacks as Iraqis head to polls ; one killed .
NEW : Obama congratulates Iraqis , mourns loss of life , praises overall security level . Polls close in Iraq ; results expected by Wednesday , U.N. says . `` It 's an opportunity we ca n't miss , '' one Iraqi voter says . Militants carry out attacks as Iraqis head to polls ; dozens killed .