Government candidate and frontrunner Mohamed Ould Ghazouani has declared himself the winner of the first round of Mauritania's presidential election, with around 20 percent of the votes still to be counted.

The 62-year-old former head of the domestic security service made the claim in the early hours of Sunday in the presence of current president Mohamed Ould Abdel Aziz, his supporters and journalists.

The ballot 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, although the opposition has raised concerns the vote could perpetuate a government dominated by military figures.

Some 1.5 million people were eligible to vote Saturday in the vast, predominantly Muslim state, which is approximately twice the size of former colonial power France and has a population of just 4.5 million.

Preliminary official results had been expected at the start of this week.

But according to a source at the Independent National Electoral Commission (CENI), Ghazouani had won 50.56 percent of the votes after 80 percent of the votes had been counted.

His nearest rival, Biram Dah Abeid, a prominent black Mauritanian slavery campaigner, has got 18.72% so far, the figures showed on Sunday.

Mohamed Ould Boubacar, who is backed by Mauritania's biggest Islamist party, has 18.13%, with support for the other two candidates in single figures.

Both men had complained of balloting irregularities and the expulsion of representatives from some polling stations.

However CENI said no major problems had been reported.

“There is only 20 percent left (to count), but that will not change the final result,” journalists quoted Ghazouani as saying.

“Our candidate will win in the first round of voting,” ruling party spokesman Sidi Ould Domane had told reporters just before voting ended.

CENI said in a statement that it would continue compiling the results from across the West African desert country before handing them over to the Constitutional Council.

In the meantime, it said it “advises the candidates to show prudence and restraint,” and hoped the calm climate seen during the campaign and on voting day would prevail.

Ghazouani — who campaigned on the themes of continuity, solidarity and security for the Saharan nation — served as Abdel Aziz's chief of staff from 2008 to last year.

Abdel Aziz surprised many of his compatriots and international observers by stepping aside after serving the maximum two five-year elected terms in Mauritania.

His decision bucked a trend in which African leaders, including in Rwanda and Congo Republic, have changed or abolished term limits to cling to power.

Abdel Aziz, who has repeatedly warned that the country could fall back into instability if his chosen candidate is not elected, is credited with reforming the army, clamping down on militants and pushing to develop remote regions.

Nevertheless, rights groups have accused the 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 the deeply-conservative state although 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 stabilization” 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.

(Source: Agencies)