Ghana's President John Dramani Mahama has been sworn in for a new term after narrowly winning an election last month.

The main opposition New Patriotic Party boycotted the ceremony Monday in the capital, Accra. They dispute the results of the vote and have challenged the election in the country's Supreme Court.

Mr. Mahama won 50.7 percent of the vote, besting NPP candidate Nana Akufo-Addo, who came in second with 47.7 percent.

International election observers said the elections were free and fair.

Mr. Mahama first took power in July after his predecessor John Atta Mills died of an illness.

The west African nation has earned a reputation for stability in an often turbulent region because of its peaceful, democratic transfers of power. Following close elections in 2008, U.S. President Barack Obama called Ghana a “model of democracy in Africa.”

Ghana, a nation of about 25 million people, is also one of Africa's fastest growing economies and is beginning to benefit from commercial oil production that began in 2010. The World Bank expects 8 percent growth for 2012 and 2013.