By Tim Cocks
ABUJA (Reuters) - Former Nigerian vice president Atiku Abubakar declared a bid to run for president as the main opposition coalition's candidate on Wednesday, ramping up a contest for the only ticket that stands a chance of unseating President Goodluck Jonathan.
Addressing supporters of the opposition All Progressives Congress (APC) in the capital Abuja, Abubakar said Nigeria was more divided than at any time since the 1960s civil war, and pledged to end the insecurity and graft plaguing Africa's top oil producer for decades. The APC holds a primary in December.
Abubakar, who defected to the APC from the ruling party in February, faces a potentially divisive struggle with other leading party officials, especially former military ruler Muhammadu Buhari, who ran against Jonathan in 2011 elections.
The board of Jonathan's ruling People's Democratic Party (PDP) has settled on him as sole party candidate for the vote scheduled for February 2015, which more or less guarantees he will be accepted by the PDP.
Jonathan, a Christian southerner, has yet to officially declare his intention to run, but is widely assumed to be going for another term and campaign posters touting his achievements have gone up all over Abuja.
"We cannot continue down this path," said Abubakar, a Muslim northerner, wearing a light blue traditional agbada or robe. "Our country is more divided today than at any time since the end of the civil war," he told hundreds of supporters beating drums and singing.
The build-up to the vote has coincided in a surge of violence by Islamist sect Boko Haram, which grabbed international attention by abducting more than 200 schoolgirls in April. They remain in captivity.
"Unspeakable horrors are now being committed daily," said Abubakar, a wealthy businessman with multiple interests.
Jonathan's assumed intention to run has been welcomed by politicians from his powerbase in the largely Christian south and but has riled many lawmakers from the mostly Muslim north.
The latter say Jonathan tore up an unwritten rule that power should rotate between the north and south every two terms, when he ran for president in 2011, after taking over from northern president Umaru Yar'Adua, when he died in 2009.
Their anger reflects wider perceptions that power has increasingly been concentrated in the more prosperous, oil-rich south since the end of largely northern military rule in 1999.
More than 800 people were killed and 65,000 displaced in three days of violence in the north after Jonathan's 2011 win.
The APC was created out of four regional parties last year - presenting a nationwide challenge. Its core support is in the north and the religiously-mixed southwest, including the commercial capital Lagos.
However, it could lose votes to Jonathan in the southwest if its pick of a northern candidate proves divisive.
Abubakar listed the achievements of the government he was in with former President Olusegun Obasanjo, including getting Nigeria's debt written off and creating Economic and Financial Crimes Commission (EFCC) to fight corruption and fraud.
Jonathan has been beleaguered by defections of senior figures, a string of oil sector corruption scandals and criticism of his government's failure to rescue the girls.
Even so, he is considered favourite to win in polls in which patronage often trumps policy.
(Additional reporting by Felix Onuah; Editing by Andrew Heavens)