Lagos , Nigeria ( CNN ) A few months before Nigeria 's national elections , both main candidates embraced and promised a peaceful election . That pledge is now under serious threat . Protesters fired gunshots and torched a local electoral office in Nigeria 's oil-rich Rivers state as they marched to protest national elections held to elect Nigeria 's next President . `` There 's been so much violence in Rivers state that it 's just not tenable , '' said Lai Mohammed , spokesman for the main opposition party , the All Peoples Congress . The All Peoples Congress says the vote has been rigged , voters intimidated and demanded that the elections held in Rivers state be canceled . The ruling party , the Peoples Democratic Party , refutes the accusation , saying the election was `` credible and the result reflects the overwhelming wish of the people of Rivers state to support President Goodluck Jonathan . '' Heavy rain eventually forced the protesters home , but there are fears that it will take more than rain to stop further protests and violence . `` We are concerned by what seems to be happening , '' said Attahiru Jega , Nigeria 's election chairman , about events in Rivers state . Nigeria has just held what are thought to be the closest elections since a return to democracy in 1999 after decades of military rule . The two main candidates are incumbent President Goodluck Jonathan and retired general Muhammedu Buhari . What is at stake in the protests in Rivers state is not whether Nigeria can hold an election , but can it hold a `` close '' election . Voting is now over and the results are being counted . Jega says the final result will likely be announced within 48 hours . The fear is that the results may not be accepted by whomever loses . And if the opposition believes it has been rigged out of victory by the ruling party , then the protests in Rivers state could spread to northern Nigeria . Over 800 people were killed in post-election violence across the north after the 2011 elections were thought to be illegitimate . And so both candidates have taken to social media to call for calm . `` I want to urge all Nigerians to also wait patiently for the Independent National Electoral Commission , INEC , to collate and announce results , '' stated Jonathan on his Facebook account . `` Fellow Nigerians , I urge you to exercise patience and vigilance as we wait for all results to be announced , '' said Buhari on Twitter .
incumbent President Goodluck Jonathan and retired general sir Buhari faced off in election . It could be the closest election since a return to democracy in 1991 after decades of military rule . There are concerns that elections should not be accepted by the losers .