About 5, 000 delegates from the Nigerian ruling People's Democratic Party (PDP) began voting for their presidential aspirant in the Eagle's Square of the capital city Abuja on Thursday evening.

The voting began at around 8 p.m. local time after three presidential contestants of the party gave speeches separately. They are President Goodluck Jonathan, former Vice President Atiku Abubakar and Sarah Jubril, a four-time presidential aspirant.

Jonathan in his speech vowed to provide strong leadership if elected.

"As we transverse this country from Bayelsa to Borno, from Cross-river state to Katsina you'll see a lot of people that are poor and have no food to eat, you'll see a lot of young men and women that need education, you'll see the challenges of technology, " he said.

"And to develop a strong economy that could handle this you need somebody as an agent of transformation. I Goodluck Ebele Azikiwe Jonathan is that agent that can and will bring the transformation we need that will start the walk of the ladder that will lead Nigeria to greatness," he added.

He promised to improve education, power generation, transportation and health in the country.

Atiku, who had been the vice president for 8 years, said he is more trustworthy, experienced and prepared for an honest task of leadership than his opponent.

"I have demonstrated over the past few years that I am ready and prepared to govern this country from day one," he said.

"Leadership is a serious responsibility which is why I have a clear program on what to do and how to do it. That program, the Atiku policy document was put together by a team of experts drawn from various sectors of our society under my leadership," he added.

Political analysts believe that the primaries will be keenly contested between incumbent President Jonathan and former Vice President Atiku.

The square has been guarded by 17,000 policemen and security personnel in prevention of any incident.

The PDP has won all of the three presidential elections in 1999, 2003 and 2007 since Nigeria began its civil rule in 1999.