Incumbent John Mahama declared winner of Ghana's presidential election

Ghana's presidential election has been won by incumbent John Mahama, the electoral commission has announced.

The commission said that Mr Mahama had won 50.7% against opposition leader Nana Akufo-Addo on 47.74%.

However, the opposition NPP says it will contest the result, accusing the governing NDC party of conspiring with commission staff to fix Friday's poll.

Ghana, one of the world's fastest growing economies, is regarded as one of Africa's most stable democracies.

The election was declared free and fair by observers of the regional body, the Economic Community of West African States (Ecowas).

"There were hiccups but not such that would grossly undermine the result of the election," said former Nigerian President Olusegun Obasanjo, who led the Ecowas observer team to Ghana.

In his first address after the result, President Mahama urged "all leaders of all political parties to respect the voice of the people".

"The voice of the people is the voice of God," he added.

Police in the capital Accra fired tear gas to disperse opposition protesters from outside the commission's offices on Sunday evening.

Tanks guarded the electoral commission and roads around the offices were barricaded by police as the results were announced.

"Ladies and gentlemen, based on the results given, I declare John Dramani Mahama president-elect," electoral commission chief Kwadwo Afari-Gyan told journalists.

He said turnout had been about 80%.