A Nigerian court rejected a challenge to President Goodluck Jonathan's victory in an April election and rejected demands by the main opposition party for a recount in several areas of the country.

Jonathan was declared winner of the April 16 election with 59 percent of the vote. But his nearest rival, former military ruler Muhammadu Buhari, who polled 32 percent, refused to accept the outcome.

Buhari's Congress for Progressive Change (CPC) party filed a petition to challenge the result in May, arguing that the vote was marred by irregularities.

The petition fails in its entirety and is hereby dismissed, Justice Kumai Akaahs told the court on Tuesday, reading out a unanimous decision by five judges.

The CPC said electoral commission computers were rigged to sway the count against Buhari, a northern Muslim, in parts of the north, and that the ruling People's Democratic Party (PDP) vote was inflated in some of its southern strongholds.

The result of the election was not successfully challenged, Akaahs said. The third respondent (Jonathan) scored the majority lawful votes cast at the election.

It is clear that the burden of proof of the allegations contained in the petition, be it criminal or for substantial non-compliance, rests with the petitioner. The petitioner did not discharge this burden.

The CPC's national chairman Tony Momoh said it would appeal the decision.

Election observers and most Nigerians say the vote was the most credible for decades in Africa's most populous nation, which had experienced virtually nothing but military rule and rigged elections for the past half-century.

It also highlighted rifts between the predominantly Muslim north and the largely Christian south.

Rioting erupted in largely Muslim opposition strongholds in the north after the victory of Jonathan, a Christian from the south, was announced. Churches, mosques, homes and shops were set ablaze and at least 500 people were killed.

Although Buhari was ahead in almost all of the states in northern Nigeria, Jonathan also picked up millions of votes in the region, giving him a credible national mandate.

Yet the PDP's parliamentary majority has been reduced and it also lost control of several states in governorship races held 10 days after the presidential vote.