Mauritania's main Islamist party has emerged during an otherwise unremarkable election campaign as an unknown quantity which observers believe will be greatly strengthened by Saturday's polls -- or killed off completely.
The former French colony's ruling Union for the Republic (UPR) is widely expected to retain power, but opinion is divided over whether Islamist party Tewassoul, only legalised in 2007, will give the favourites a bloody nose.
The mainly Muslim republic on the west side of the Sahara desert is seen by Western leaders as strategically important in the fight against Al-Qaeda-linked groups within its own borders, in neighbouring Mali and across Africa's Sahel region.
Around a third of its 3.4 million people are eligible to vote in the first parliamentary and local polls since 2006, a test of strength for President Mohamed Ould Abdel Aziz five years after he came to power in a coup and four years after he won a widely contested presidential vote.
Around 1,500 candidates from 74 parties representing the administration and the so-called "moderate" opposition are registered to vie for 147 seats in parliament and the leadership of 218 local councils dotted across the shifting sands of the vast nation.
But Tewassoul is the only member of the so-called "radical" opposition, the 11-party Coordination of Democratic Opposition (COD), contesting the polls.
It describes its participation as a form of struggle against the "dictatorship" of Abdel Aziz.
The rest of the COD coalition said it would "boycott this electoral masquerade" after talks on how the vote should be run broke down in early October.
The UPR is the only party fielding candidates in every constituency, making it a strong favourite over Tewassoul, its closest rival, and the People's Progressive Alliance of parliament leader Messaoud Ould Boulkheir.
Tewassoul, associated with the Mauritanian branch of the Muslim Brotherhood, professes to hold more moderate beliefs and goals than the country's jihadist fringe.
A sophisticated political entity with a youth wing and a women's group, Tewassoul has a website, YouTube channel and Facebook and Twitter accounts.
It draws support from female voters and Mauritania's young, urban middle-class, but remains a fringe party with modest electoral traction.
Its main policies in recent years have included anti-Israel activism and support for increasing the use of Arabic in higher education.
UPR national campaign director Mohamed Mahmoud Ould Jaavar told a meeting in the capital Nouakchott on Tuesday that Tewassoul must "set themselves apart from the Islamists who have committed a lot of damage in the Arab and Muslim world".
"No party has the right to appropriate Islam, which is the religion of all of us, for itself," he said.
Observers envisage two possible scenarios, in which the elections either give Tewassoul a major boost or stymie the nascent party.
"Islamists face several challenges, including President Abdel Aziz's success in co-opting their rhetoric, the pitfalls of preserving Islamic principles while navigating electoral politics, and the need to respond to jihadism," analyst Alex Thurston said in a report on Tewassoul for the Carnegie Endowment think tank.
"But the trends that gave rise to Islamism continue: urbanisation proceeds, social inequality remains, and mosques and Islamic schools still proliferate, allowing Islamists to expand their influence in urban spaces and reach new audiences, particularly among the youth."
The polls are also a test for the rest of the COD, which says election day will "intensify the political crisis in the country".
It says it is counting on a "relatively large" proportion of the electorate to heed its call for a boycott.
Ahmed Ould Daddah, one of the main leaders of the "radical" opposition, warned on Tuesday that the UPR was "about to commit fraud as it did in the 2009 presidential election".
The "moderate" section of the opposition, which decided not to follow the COD boycott, includes the three-party Coordination for a Peaceful Alternative, a key player in Mauritania's nascent democratic process responsible for negotiating the establishment of the independent electoral commission which will supervise the vote.
Following independence from France in 1960 and the ensuing one-party government of Moktar Ould Daddah, deposed in 1978, Mauritania had a series of military rulers until its first multi-party election in 1992.