Mauritania's ruling party candidate Mohamed Ould Ghazouani has won the presidential election with 52 percent of the vote, the electoral commission announced Sunday, with opposition candidates crying foul.
Ghazouani easily beat main opposition opponents Biram Ould Dah Ould Abeid (18.58 percent) and Sidi Mohamed Ould Boubacar (17.87 percent), according to the official figures from Saturday's polls.
Former prime minister Boubacar, addressing a news conference along with three other candidates, charged that "multiple irregularities... eliminated any credibility" in the election, which was to be the first democratic transfer of power in the West African desert nation.
"We reject the results of the election and we consider that they in no way express the will of the Mauritanian people," he said, vowing the opposition would use "every legal means" to challenge them.
The CENI electoral commission said voter turnout was 62.66 percent.
With a clear majority, the 62-year-old Ghazouani, former head of the domestic security service, has won outright with no need for a second-round runoff election.
Ghazouani had already declared himself the winner in the early hours of Sunday in the presence of outgoing president Mohamed Ould Abdel Aziz, his supporters and journalists.
Second-placed Abeid, an anti-slavery activist, told the opposition news conference: "We are launching an appeal to the Mauritanian people... to resist, within the bounds of the law, this umpteenth coup d'etat against the will of the people."
Incidents broke out between protesters and police following Ghazouani's declaration in the capital and in northwest Nouadhibou, the only province where he did not come in first.
The opposition said they were planning protests from Monday afternoon.
"We will organise protests, this is our constitutional right," Mohamed Ould Moloud, who got 2.44 percent of the vote, told the news conference late Sunday, stressing they would be peaceful.
Baba Hamidou Kane, who polled 8.71 percent, said the four opposition candidates would lodge an official protest with the electoral commission on Monday.
Although the vote is the first in Mauritania's coup-strewn history that looks set to see an elected president complete his mandate and transfer power to an elected successor, the opposition has raised concerns that the vote could perpetuate a government dominated by military figures.
Some 1.5 million people were eligible to vote in the vast predominantly Muslim state, which is approximately twice the size of former colonial power France but has a population of just 4.5 million.
CENI advised all candidates "to show prudence and restraint", and hoped the calm during the campaign and on voting day would prevail.
Both Abeid and Boubacar had complained of balloting irregularities and the expulsion of representatives from some polling stations. However CENI said no major problems had been reported.
Ghazouani -- who campaigned on the themes of continuity, solidarity and security -- served as Abdel Aziz's chief of staff from 2008 to last year.
The outgoing president is a general who originally came to power in a 2008 coup. He won elections a year later and was again elected in 2014 in polls boycotted by the opposition.
Abdel Aziz repeatedly warned that the country could fall back into instability if his chosen candidate was not elected. He is credited with reforming the army, clamping down on jihadists and pushing to develop remote regions.
Nevertheless, rights groups have accused Mauritania's government of restrictions on freedom of expression and assembly, while calling on the nation to do more to counter violence against women and slavery, which persists in this deeply conservative state even though it was officially abolished in 1981.
Authorities rejected an opposition request for foreign observers at the election.
All of the candidates promised improvements in the standard of living, though economic growth at 3.6 percent in 2018 is insufficient to meet the needs of a fast-growing population, according to the World Bank.
The World Bank has welcomed the "macro-economic stabilisation" of the country, where annual growth is expected to average 6.2 percent between 2019 and 2021.
But it has called for barriers to be removed in the private sector, pointing in particular to corruption, as well as difficult access to credit.
Nouakchott, Mauritania | AFP