Sierra Leone President Ernest Bai Koroma has been sworn into office for a second term after winning last week's election.

In a speech Friday to cheering supporters in Freetown, President Koroma promised to fight corruption and attract foreign investment.

The United States congratulated President Koroma in a statement, saying the election has shown the progress Sierra Leone has made toward improving democratic institutions after the country's civil war ended a decade ago.

President Koroma took the oath of office hours after the head of the county's National Election Commission announced that Mr. Koroma won re-election with more than 58 percent of the vote.

“Ernest Bai Koroma has been duly elected President of the Republic of Sierra Leone at the presidential election of 2012.”

President Koroma faced eight challengers in the election and needed to win at least 55 percent of the vote to avoid a runoff. Mr. Koroma's main rival, Julius Maada Bio, took just over 37 percent of the vote.

No results were announced for parliamentary elections, which took place at the same time as the presidential poll on November 17.

Election officials say last week's vote drew a large turnout. Observers said the voting was peaceful and transparent.

The elections were the third set of polls since the end of Sierra Leone's decade-long civil war in 2002.

Mr. Koroma won the last presidential poll in 2007 in a runoff vote and has been praised for his progress on improving the country's infrastructure.

Main opposition candidate Bio briefly served as military leader of the nation in 1996 before handing power to a short-lived civilian administration.