Preliminary voter registration statistics in Nigeria appear to show the country's Muslim north holds an edge in the oil-rich nation's coming elections, posing a new challenge to President Goodluck Jonathan's poll bid.

Jonathan, a Christian, is the candidate of Nigeria's long dominant ruling party. But he faces several strong Muslim opposition party candidates in his bid to officially win the job he gained last year after the death of Nigeria's elected Muslim leader.

He will have to win over a reluctant north to win in the April 9 election. Critics also note that fraud has marred elections here since Africa's most populous nation became a democracy in 1999.

Numbers released by the Independent National Electoral Commission suggest states in Nigeria's north have more than 36 million voters, compared to the largely Christian south having 31.6 million. In total, the commission says 67 million voters registered ahead of April's presidential election.

Commission spokesman Kayode Idowu confirmed the registration figures Tuesday, but declined to offer any "analysis." His hesitancy comes as Nigeria's ethnic and religious divisions have made any sort of numerical count between north and south impossible since the West African nation won its independence from Britain in 1960.

In the time since, Nigerian leaders have buried the results of censuses conducted on behalf of the state out of fears of inflaming divisions between its largely Christian south and Muslim north. Population figures used by international organizations like the World Bank and the U.N., pegging the nation's population at around 150 million people, remain largely estimates.

More than 250 ethnicities call Nigeria home, a kaleidoscope of cultures that largely intermingle freely with each other. However, power has not been equally distributed in the country since independence. Out of 50 years, northern military rulers or leaders have held power for 39 years. Former president and military dictator Olusegun Obasanjo, a southern, held power for 11 years.

Those in the south often point to that disparity in rule, noting some of the country's most corrupt leaders robbed the nation's oil revenues during that period. Meanwhile, some elites in the north still say the ruling People's Democratic Party presidential primary should have gone to a northerner to satisfy an unwritten power-sharing agreement.

Meanwhile, opposition parties continue to make headway in cutting into the ruling party's dominance.

The Action Congress of Nigeria, for instance, firmly grips Nigeria's commercial capital of Lagos. They could peel away many of the 6.2 million votes that comprise Lagos alone, making a Jonathan victory even more difficult.

How the ruling party will respond to that remains unclear.

"Everybody I spoke to — in Lagos, Asaba, Awka, Enugu and Abuja — was certain that fraudulent elections could spell lasting doom this time around," newspaper columnist Okey Ndibe recently wrote. "Yet, after witnessing the impunity that passed for party primaries, it's difficult to be hopeful in the prospects of credible elections in April."