John Dramani Mahama has been sworn in as Ghana's next president following his narrow win in elections last month. The opposition is disputing the result.

After being sworn in Monday Mahama gave a speech saying "we all have a role to play" in making Ghana a better country, while acknowledging unspecified troubles still facing one of West Africa's most stable democracies.

Mahama, the former vice president who took the helm in July following the unexpected death of President John Atta Mills, was elected with an absolute majority of 50.7 percent in the December poll. His main challenger, Nana Akufo-Addo, won 47.7 percent.

The New Patriotic Party claims Akufo-Addo won the election and has brought a case to the nation's Supreme Court.