NEW : U.N. Secretary-General Ban Ki-moon congratulates the Libyan people on the election . Some polling centers remain open after violence stopped voters from casting ballots . The United Nations says it is investigating reports of voting irregularities in some areas, but there are no immediate plans to suspend or cancel voting. The 200-seat national assembly will help rebuild the nation , create institutions .
NEW : U.N. Secretary-General Ban Ki-moon congratulates the Libyan people on the election . Some polling centers remain open after violence stopped voters from casting ballots . Preliminary results of the parliamentary vote could be announced Sunday or Monday , an official says . The 200-seat national assembly will help rebuild the nation , create institutions .