People in Guinea-Bissau go to the polls to elect a new president in an effort to stabilize a fragile state plagued by powerful cocaine cartels and a military coup since two years ago.

An election commission source says over 3000 polling stations opened across the country for the Sunday runoff vote.

Former finance minister Jose Mario Vaz is facing Nuno Gomes Nabiam, the former chair of Bissau's civil aviation agency. Vaz came first in the first round with more than 40 percent of the votes while Nabiam, who is said to have been supported by the country’s army, garnered 25.1 percent of the ballots cast.

Since the 2012 coup, the poverty-stricken country has been stagnating under the rule of a transitional government.

A powerful military backs the interim government, yet both have failed in revamping the economy or curbing drug trafficking.

Critics say the role of the army remains unclear, taking into account that it intervened in 2012 to stop the voting process.

Officials and voters expect the presidential and parliamentary polls to put an end to decades of instability in the African nation.

UN Secretary General Ban Ki-moon has recently praised the election, saying they had "clearly expressed their desire for the full return to constitutional order in their country."

The country has also witnessed several coups since it gained independence from Portugal in 1974. No elected leader has served a full-term in office.

The new leader and government will also face a difficult task of fighting poverty as two-thirds of the country’s population of 1.6 million live below the poverty line.

The impoverished West African nation is plagued by an ailing economy, cocaine trafficking and widespread corruption.