It's Cellou Dalein Diallo's third time in the running to become Guinea's next leader. The 68-year-old hopes this is the year he will succeed after voters cast their ballots in the first round on Sunday.

Diallo is Guinea's leading opposition politician and faces the incumbent President Alpha Conde yet again alongside 10 other candidates.

Conde is running for a controversial third term after the leader pushed through changes to the constitution, which sparked protests and subsequent deadly police crackdowns.

Diallo was a former prime minister under the authoritarian leader Lansana Conte.

He is a self-described technocrat and hopes his younger age compared to 82-year-old Conde will stand in his favour.

He says the current leader should "retire with dignity" and is arguing for change after Conde's 10-year rule.

He says Conde has a "catastrophic record" as poverty is rife in the mineral-rich country.

There have been fears that the recent tensions have taken on an ethnic dimension, with Conde accused of exploiting divisions during the campaign -- a charge he denies.

Guinea's politics are mainly drawn along ethnic lines: the president's base is mostly from the ethnic Malinke community and Diallo's from the Fulani people.

Diallo's camp is suspicious of the fairness of the vote, and some supporters have warned they will not be "robbed" of victory.

"We will do exactly as President Obama did. (If) we have our own results, we will tweet them," said Diallo's right-hand man, Fode Oussou Fofana.