A candidate who came second in Mauritania's June 21 presidential election rejected results announced by the national election commission, contending that fraud and irregularities marred the voting.
President Mohamed Ould Abdel Aziz won another five-year term with 82 percent of the vote, the election commission announced on Sunday following an election that was boycotted by most opposition parties.
Anti-slavery campaigner Biram Ould Dah Ould Abeid came in a distant second with nine percent of the vote.
If these elections were held under normal circumstances, I would get between 35 and 40 percent
"We have filed an appeal at the Constitutional Council," Ould Abeid told a news conference, accusing the government of having influenced the election in order to favour President Abdel Aziz, Reuters news agency reported.
"If these elections were held under normal circumstances, I would get between 35 and 40 percent," he said in the Mauritanian capital, Nouakchott on Tuesday.
Abdel Aziz, who assumed power in a coup in 2008 and won elections a year later, has been a staunch ally of the West.
The National Forum for Democracy and Unity, a coalition of main opposition parties, decided to exclude themselves from the contest when the election date was chosen without their input.
They complained that Abdel Aziz's control of state institutions would ensure his victory and described the vote as "grotesque theatre", AP news agency reported.
Abdel Aziz hails from the country's ethnic Arab elite that long has dominated the ruling class, but his policies have made him popular among the poor black majority.
Two other unsuccessful candidates in the election have accepted the results and congratulated the president.