By Felix Onuah and Camillus Eboh
ABUJA (Reuters) - Nigerian President Goodluck Jonathan begins his first full term at the helm of Africa's most populous nation on Sunday with expectations running high that he will push ahead with reforms and try to heal regional rifts.
Heads of state from across Africa, foreign dignitaries, religious leaders and traditional rulers are due to attend a swearing-in ceremony and military parade in the capital Abuja to mark the start of his four-year term.
The former zoology student won elections last month which, while far from perfect, were deemed to have reflected the will of the people in a nation which had known virtually nothing but military rule and rigged votes for the past half-century.
Jonathan emerged from the polls with a credible mandate, having won 59 percent of the vote, but with his ruling People's Democratic Party (PDP) chastened by a weaker parliamentary majority and the loss of several powerful state governorships.
Many Nigerians said they felt their vote had counted for the first time. The onus to perform is now on Jonathan, who inherited the presidency last year when his predecessor Umaru Yar'Adua died.
"The success of the election has upped the game in terms of the expectations of what can be delivered by a Jonathan presidency," said Dapo Oyewole, director of the Center for African Policy and Peace Strategy think tank.
"There is going to be a much higher level of scrutiny. Everybody is going to be watching every step he makes."
The vote threw religious and ethnic fault lines into sharp relief. Hundreds were killed in rioting in parts of the mostly Muslim north after his victory and his main rival, former military ruler Muhammadu Buhari, has challenged the result.
His relationship with his opponents will be key if Jonathan, a southern Christian, is to galvanize support for reforms and govern strongly.
The first big test will be his choice of ministers.
"It is a delicate balancing act," said Oyewole.
"He has to balance out the regional interests to ensure the cabinet displays a federal character, he has to reflect a religious coloration that ensures different parts of the country are carried along, but he is also going to have to reward some of the people that backed him," he told Reuters.
Jonathan is the first head of state from the restive oil-producing Niger Delta and also carries the high expectations of his home region on his shoulders. He brokered an amnesty in 2009 which ended years of attacks on oil facilities, but thousands of former gunmen remain without jobs.
"People are very optimistic based on hope rather than reality," said Bismarck Rewane, head of Lagos-based consultancy Financial Derivatives.
"If those expectations are not managed, a few months down the road he will be getting the blame for things that are beyond his control," he told Reuters.
Jonathan will also have to deal with the growing threat from radical Islamist sect Boko Haram in remote northeastern Nigeria, which has been carrying out almost daily killings and fire bombings of police stations with impunity.
Car bombs, claimed by a militant group from the Niger Delta, killed at least 10 people close to an independence day parade in Abuja last October and security was tightened in the capital days ahead of Sunday's ceremony.
Joint police and army checkpoints were set up on all roads into the city and helicopters buzzed overhead.
Jonathan is serving what would have been the second term of late northern president Yar'Adua and there is an expectation among the northern elite that at the next elections in four years, a northern candidate will take the ruling party ticket.
But should Jonathan succeed with his reform plans, particularly privatizing the power sector and ending chronic power shortages, popular opinion could again swing behind him.
"People will be looking for tangible results and that will be a key determinant of his political future come 2015," said Oyewole of the Abuja-based think tank.