Morocco has recalled its ambassador to Nigeria, in a row over whether the president of Nigeria is trying to use the king of Morocco to win over Muslim voters before Nigeria's elections this month.
Last week, the Moroccan royal palace said the king had declined a request for a telephone conversation with Nigerian President Goodluck Jonathan. Nigeria's foreign ministry denied the snub on Monday and said the two leaders had spoken extensively.
Jonathan, a Christian from southern Nigeria, will face former military ruler Muhammadu Buhari, a Muslim northerner, in elections on March 28. The election is expected to be the most closely fought since the end of military rule in 1999.
Nigeria's population is roughly split between Christians and Muslims. Both parties, the ruling People's Democratic Party and the All Progressives Congress, have been using religion to bolster support.
"Morocco confirms, in the clearest and strongest terms, that there has never been a phone conversation between the King Mohammed VI and the president of this country," a statement from the Moroccan foreign ministry said.
The Nigerian foreign ministry said it was "preposterous to suggest that Mr. President's telephone call to the Moroccan monarch was intended to confer any electoral advantage."
A spokesman for the ministry did not immediately respond to requests for comment on the recall.
Morocco cited "the hostile, recurrent and unfriendly positions of the Nigerian government with regard to the Moroccan Sahara issue and the sacred Arab-Muslim causes" as a reason for declining Jonathan's call.
Nigeria is one of the main supporters, along with Algeria and South Africa on the continent, of the independence movement Polisario Front in the disputed Western Sahara.
The territory is a tract of desert the size of Britain that has lucrative phosphate reserves and possibly oil, is the focus of Africa's longest-running territorial dispute, between Morocco and the Polisario guerrillas.