Mauritanian President Mohamed Ould Abdel Aziz vowed to work for national unity following his landslide 82-percent victory in weekend elections that were boycotted by the opposition.

Abdel Aziz, 57, pledged "to be the president of all Mauritanians and to guarantee the rights of all citizens," according to a text read out by his campaign director Sidi Ould Salem on Monday.

Mauritania's incumbent leader Mohamed Ould Abdel Aziz has won presidential polls with an overwhelming 81.89 percent of the vote, preliminary results showed Sunday, after his main rivals boycotted a process they rejected as a sham.

Abdel Aziz was firmly ahead of anti-slavery candidate Biram Ould Dah Ould Abeid, who obtained 8.67 percent of the ballot, results published by the national electoral commission showed.

Counting was underway in Mauritania's presidential election on Sunday with incumbent Mohamed Ould Abdel Aziz expected to win handily after his main rivals boycotted a process they regard as a sham.

The former general, who seized power in the northwest African nation in an August 2008 coup, campaigned strongly on his success in fighting armed groups linked to al-Qaida at home and in neighboring Sahel nations.

Mauritanians on Saturday cast ballots in a presidential election that incumbent Mohamed Ould Abdel Aziz was expected to win handily as main opposition rivals boycotted the vote in the largely desert nation.

The ex-army general, who seized power in the northwest African nation in a August 2008 coup, has campaigned strongly on his success in fighting armed groups linked to al-Qaida at home and in neighboring Sahel nations.

Mauritania's President Mohamed Ould Abdel Aziz has responded defiantly to an opposition boycott of this month's presidential election, calling for "100 percent" turnout in a vote he is widely expected to win.

Abdel Aziz has urged "everyone to come out and vote" in the June 21 election, since campaigning began last week.

The Mali government signed a ceasefire deal with three rebel groups in the northern desert Friday, the African Union's negotiator announced, after the Tuareg and Arab insurgents captured the flashpoint town of Kidal.

The town is the cradle of Mali's separatist movement, which wants independence for a vast swathe of northern desert it calls "Azawad" and which has launched several rebellions since the 1960s.

Mauritanian leader Mohamed Ould Abdel Aziz will face four other candidates including a woman and an anti-slavery activist in the June 21 presidential election, the constitutional court confirmed on Tuesday.

Court officials named Lalla Mariem Mint Moulaye Idriss, the second woman to run in the country's history, on a list of approved candidates which also included opposition party leaders Boidiel Ould Houmeid and Ibrahima Moctar Sarr.

A woman has put forward a rare bid for the presidency of Mauritania, a west African nation run under strict Islamic law, the country's Constitutional Council said Wednesday.

"Lalla Mariem Mint Moulaye Idriss dropped off a file at the Constitutional Council containing her candidacy for the June 21 presidential elections," the body said in a statement.

Mauritania's radical opposition coalition said Sunday it has decided to boycott next month's presidential election, accusing the nation's rulers of blocking dialogue over how the vote will be run.

The announcement by the spokesman for the National Forum for Democracy and Unity (FNDU) followed a meeting of the coalition on Saturday amid a row over the timing of the June 21 vote and opposition demands for electoral reform.

The mostly desert nation of Mauritania will go to the polls to pick a new president on June 21, the official news agency said on Monday.

"The electoral college is convened on Saturday June 21, 2014, and in the event of a second round, on Saturday July 5," the agency reported, citing a government decree.