Election In Mauritania: General Mohamed Ould Abdel Aziz Wins

Rzeizim said parliament speaker Messaoud Ould Boulkheir came in second with 16 percent, while veteran opposition leader Ahmed Ould Daddah was third with 13 percent.

A statement from the group of four challengers read: "We firmly reject these prefabricated results, secondly we call on the international community to put in place an inquiry to shed some light on the electoral process."

Lawyer Bouhoube Yni of the nation's independent electoral commission — whose 15 members represent the rival political parties — said no serious complaints or proof of fraud had been submitted so far.

Several hundred international observers are monitoring the vote. But none of the main groups, including those from the African Union and French speaking countries, have released their findings. Mahamat Saleh Annadif, of the African Union, said the body's monitors were still returning to Nouakchott and the mission would release its results Monday.

Messaoud spokeswoman Amal Mint Abdallahi said the opposition was preparing to formally submit its complaints. She alleged Aziz's camp had handed out ballots pre-marked in his favor and paid voters to use them to vote; the voters then returned empty ballots to Aziz supporters to prove they had cast ballots for him, she said.

Abdallahi also alleged Aziz's camp fabricated false identity cards and illegally inflated voter lists.