ABUJA (Reuters) - Nigeria's post-election riots have highlighted the likelihood of further bloodshed and growing radicalism in a Muslim north that feels ever more marginalized from a richer and more dynamic south.
Although it is too early to see the troubles in the north as a sign of Africa's most populous nation coming apart, President Goodluck Jonathan and northern leaders face a serious challenge to avoid a drift toward greater polarization.
Churches, homes and shops have been burned and an unknown number of people stabbed, hacked and shot to death since Jonathan, a Christian southerner, defeated Muslim northerner Muhammadu Buhari in a presidential election the opposition says was rigged.
Regardless of whether there was foul play or not, the map of results showed the reality of Nigeria's divide. Buhari won heavily in the north and Jonathan in the south -- not that the president did not pick up votes in parts of the north.
"Sometimes there is a pretence we have gone beyond religion and ethnicity, but it is the same all over the country," said Mannir Dan-Ali, editor of the Abuja-based Daily Trust.
In a sign of how concerned the presidency was, it put out a statement urging foreign media to stop referring to a "Muslim north" and "largely Christian south" and stressing that Jonathan had a mandate across Nigeria.
As always, the first to suffer in the violence were those from other parts of Nigeria -- many of them small business owners -- who have traded in the north for generations.
Known supporters of Jonathan's ruling People's Democratic Party were predictably in the firing line.
But rioters also vented their anger on a local elite seen as complicit in the north's decline while living high on its personal cut of oil wealth handed down from Abuja.
"It is a revolution. Emirs are being attacked, the big men are being attacked," said Yinka Odumakin, spokesman for Buhari, a disciplinarian during nearly two years in power in the 1980s.
"The poverty in north Nigeria is only increasing and there is an army of unemployed youths who are looking at the benefits of the elite. They look to General Buhari. He was the only one who showed he would lock these ogas (big men) up."
The north has long been the poorest, unhealthiest, least educated part of Nigeria, lacking the south's oil resources, banks and businesses. But under a succession of military rulers until 1999, it had the compensation of holding power.
Jonathan's rise underscored the humiliating loss of influence ever since. He came to office when his northern predecessor Umaru Yar'Adua died in office last year and many northerners argued it was still their turn to rule.
But Jonathan, the first president from the oil-producing Niger Delta, secured the ruling party's nomination.
Although the vote was regarded by observers as the fairest for decades, very high turnout figures in parts of the south raised fears in the north that they had been inflated.
"When results started coming in I had text messages saying things like 'we have been conquered'," said Dan-Ali.
Meanwhile, the decline of the few industries -- such as textile mills unable to compete with Chinese imports -- deepened northern poverty just as oil and services-led growth in the south has driven overall expansion to around 7 percent a year.
"All that the violence does is make people in the south say let's have done with the north," said business consultant John Adeleke, based in the giant southern commercial hub of Lagos.
"It's not within the interests of the northern elite to allow any form of split but it is to allow them to have enough dissent to extract concessions from Jonathan."
Whether Jonathan can deliver concessions is another question given the various pledges he had to make to interest groups from elsewhere to assure his victory.
To restore order he has the army, pledged to loyalty and with its top ranks no longer dominated by northerners, but a heavy handed response could fan the flames and cause even more casualties.
Past bouts of killings have left thousands dead in the north and were followed by reprisals in the south. One such episode led to civil war in which one million were killed in the 1960s.
Militants from the Niger Delta, who gave up weapons under an amnesty two years ago, said they would not retaliate for now over the latest killings but made clear it was a possibility.
Just as uncomfortable for many in the north is that what happens there is irrelevant to much of the country.
Businesses and homes in the north are being destroyed and its cities are paralyzed. Not in the south, hundreds of miles away. Nigerian shares rose their most in a month on the worst day of the violence.
The north's despair is fertile ground for Islamic radicalism. A localized Islamist sect is accused of killings in the far northeast. Unexplained bombings in the campaign run-up showed the capacity for major attacks very much exists.
Nigeria's next potential flashpoint is next week at elections for powerful governors of 36 states.
Because of the violence in the north, there are doubts over whether these can even take place there.
Election offices have been destroyed and national youth corps workers, widely praised across Nigeria for running such a smooth ballot, have been among those murdered.
If the elections do not happen in the north, it could cause trouble because Buhari's supporters will have lost another chance to take at least some power.
If they do go ahead, then the results could again mean friction. Jonathan's party wants to secure the states so he can pursue his agenda, but if it does too well it will again be accused of rigging and there could be more killings.
"The north has become marginalized, but some people are saying don't just lament about it, get control at state level and make sure the people who are elected don't turn into the same kind of people you are complaining about," said Dan-Ali.
"If Jonathan is able to do what he has been saying he will do, that will be a new beginning. If he addresses security and power and corruption that will be positive. It is only when the problems begin to be addressed that the question of where people come from will no longer matter."
(Editing by Giles Elgood)