Ghana opposition candidate not ready to concede

The opposition candidate in Ghana's presidential polls said he is not ready to concede defeat after alleging a "pattern of fraud", but has not yet decided whether to challenge the results in court.

Nana Akufo-Addo, a 68-year-old human rights lawyer, made the comments on Monday after his party alleged irregularities in the election won by incumbent John Dramani Mahama, as the country seeks to maintain its reputation as a model African democracy.

"For me, the image of Ghana shouldn't be a falsehood," Akufo-Addo told reporters at his home.

"It shouldn't be that on the surface we have democracy, but underneath we have something else. We want the democracy of Ghana to be a genuine one."

The son of a former president said "there would seem to be a serious case for saying something seriously went wrong", but added that the party was continuing to investigate and would decide how to proceed. He expected a decision in the coming days.

A crowd of loyalists had gathered outside Akufo-Addo's house in support for the candidate, who lost 2008 elections by less than one percentage point.

President Mahama received welcome support from Washington Monday as the White House urged all Ghanaians to accept the result of their election and congratulated him on his victory.

According to the electoral commission, Mahama won the election held over Friday and Saturday with 50.70 percent of the votes cast, compared to Akufo-Addo's 47.74 percent.

Observers from the Commonwealth, West African bloc ECOWAS and local group CODEO -- which deployed election observers -- all said the vote appeared peaceful and transparent but Akufo-Addo said Monday he was not ready to admit defeat.

"The United States congratulates President John Dramani Mahama and the people of Ghana for the successful election on December 7," White House press secretary Jay Carney said in a statement.

"The United States encourages all parties to accept the results and to use the appropriate legal processes to resolve any electoral disputes."

Late in the afternoon, Benin's President Thomas Boni Yayi, also the current head of the African Union, visited Akufo-Addo's home and the two had a brief conversation with reporters in the room, but their discussions could not be heard.

When the gates opened for Yayi's convoy to enter Akufo-Addo's compound, dozens of supporters streamed through with some approaching his front door to shout encouragement at their party's leader.

The stakes are especially high in the West African country with a booming economy fuelled in part by a new and expanding oil industry.

Addressing a celebratory crowd of supporters in the central Accra on Monday, Mahama sought to move the country past the "hard fought campaign".