(AFP) - Guineans go to the polls on Sunday to choose a president, with the 82-year-old incumbent bidding for a third term despite mass protests against the move and concerns about democratic backsliding.

The election caps a tense political campaign marked by insults traded between President Alpha Conde and his leading rival Cellou Dalein Diallo.

It also follows months of political unrest in the poor West African nation, where mass protests against a Conde third term that first erupted in October last year have left dozens of people dead in a crackdown by security forces.

Conde pushed through a new constitution in March, arguing that it would modernise the country. But the move controversially allowed him to bypass a two-term limit for presidential terms.

After decades as an opposition activist, Conde became Guinea's first democratically-elected president in 2010 and won again in 2015.

Rights groups have become increasingly critical of the president, however, accusing him of veering towards authoritarianism.

Diallo, 68, now Guinea's leading opposition politician, was formerly a prime minister under authoritarian leader Lansana Conte.

Sporadic clashes between rival supporters have broken out across Guinea in recent days, sparking fears of further violence on polling day.

- A test of Conde's policies -

Kabinet Fofana, a Guinean political scientist, cast the election as a battle between Conde promoting his record in office, and his opponent arguing for change after a decade of his rule.

"This election will play out for Alpha Conde on (his ability) to promote his public policies," Fofana said.

But Conde's advanced age will weigh on voters' minds, according to Fofana.

Diallo raised the issue several times during the campaign, even encouraging Conde to "retire with dignity".

The sharply-dressed president has brushed off the gibes, however, and conducted a vigorous helicopter tour of the country.

Known as being quick to anger, Conde spent decades as an opposition activist, and was even sentenced to death in absentia by a former autocrat, before finally taking power in 2010.

He beat Diallo to the presidency then, and pulled off the feat again when he was re-elected in 2015.

Among other things, Conde promised to boost the economy of the nation of some 13 million people, to tackle corruption and increase Guinea's lamentable electricity access.

He has stuck to a similar script during this year's campaign, pledging to make Guinea "Africa's second (economic) power after Nigeria".

- 'Only promises' -

But Guineans interviewed by AFP expressed deep frustration about the state of the country, regardless of their political stripes.

The former French colony is rich in minerals such as bauxite, iron and gold, and has abundant fresh-water resources. However it remains one of the poorest countries in the world.

"In 10 years, Alpha Conde has done nothing," said Aminata Barry, a 36-year-old opposition supporter, adding that he had made "only promises".

Conde nonetheless retains a bedrock of supporters who hail his efforts at economic revival. He drew huge crowds on the campaign trail, where he dismissed his many critics.

"Despite his age, we want him for the future of our youth," said lawyer Sekou Diakate, 47, who was among thousands who attended a Conde rally Friday.

Diallo -- a self-described technocrat -- has pointed to Conde's "catastrophic record" and took to pointing at his watch while campaigning, symbolising that the octogenarian's time has run out.

"He no longer has the physical and intellectual capacity to carry out this demanding function," he recently told French broadcasters.

The vote is the first in a string of elections scheduled across West Africa, including in Ivory Coast, Burkina Faso, Ghana and Niger.

Some of the major issues in these elections bear a striking semblance to the political debate in Guinea.

In Ivory Coast, for example, incumbent President Alassane Ouattara is running for a third term after revising the country's constitution. The October 31 vote will also take place in a highly tense atmosphere.

Activists are concerned that a win for Conde would bode ill for democratic norms in the region.

Some 5.4 million registered voters are due to cast their ballots, and initial results are expected to be announced several days afterwards.

A second round is scheduled for November 24.

© Agence France-Presse