Guinea-Bissau will hold a second round in its presidential election after no candidate secured a majority in the first, according to the country's election commission.

Jose Mario Vaz, Guinea-Bissau's former finance minister and a member of the African Party for the Independence of Guinea-Bissau and Cape Verde, will compete with Nuno Gomes Nabiam, an army-backed candidate, for the country's presidency on May 18.

Vaz won 40.99 percent of total votes in the first round and Nabiam came second with 25.14 percent, according to election commission figures that were released on Wednesday.

Al Jazeera's Catherine Soi, reporting from Guinea Bissau, said people were wary of a second round vote.

"They worry about what might happen, and they are scared of what the army might do, even though the chief of staff of the army has said that the country's troops will respect the result," our correspondent said.

Thirteen politicians were in the running for the position before the first round of voting on April 13.

The presidential and parliamentary elections are meant to give the country a fresh start, after its independence from Portugal in 1974 resulted in decades of instability.

Coup and corruption

Guinea-Bissau's last election, in 2012, was abandoned after the military seized power between rounds.

Corruption has festered under the transitional, military-backed government and voters hope the election will help combat this nepotism and jump start the economy.

First vote since the 2012 coup

The international community is watching the elections closely because the country has become a transit hub for the cocaine trade. The head of the military is under federal indictment in the US.

But Ban Ki-moon, the UN secretary general, applauded Guinea-Bissau for holding peaceful polls, saying that the people "clearly expressed their desire for the full return to constitutional order in their country".

Almost three-quarters of Guinea-Bissau's eligible voters turned out for the first round of voting.

No elected leader has served a full term in office since the country gained independence.

Source: Agencies