Goodluck Jonathan has been sworn in for a full four-year term as president of Nigeria and is now faced with the challenge of uniting a country that has seen deadly post-election violence despite what observers described as the fairest vote in more than a decade.
Hours after the ceremony, a series of bomb blasts at an army barracks in Bauchi in the country's north-east killed at least five people, according to a police official.
The stately ceremony at the main parade ground in Nigeria's capital of Abuja came just over a year after Mr Jonathan was sworn into office to complete the term of late president Umar Musa Yar'Adua. Mr Yar'Adua's death catapulted the former vice president to power last year, but April 16 elections solidified his hold on the presidency.
"You have entrusted me with your mandate and I will never, ever, let you down," he said during his inaugural address.
Observers heralded the April 16 vote as the fairest election that Nigeria has held since it became a democracy 12 years ago. Nigeria has been plagued by military coups for much of its 50 years of independence and all previous elections had been severely flawed.
However, the April vote was marred by post-election riots that left hundreds dead, highlighting religious and ethnic fault lines in Africa's most populous country. Human Rights Watch said more than 800 people, both Christian and Muslim, died in the election-related attacks and counter-attacks.
During his inaugural address, Mr Jonathan said that development would remedy those divides. "Together we will unite to improve the living standards of all our peoples, whether in the north, or in the south, in the east, or in the west. This is our decade of development," the president said. "We will not allow anyone to use our difference in creed or tongue to set us against one another."
The nation of 150 million people with more than 150 ethnic groups is broadly divided between the Christian-dominated south and the Muslim north. The post-election violence spread quickly across northern states after early results showed that Mr Jonathan, a Christian from the south, was winning.
Many northerners believed someone from their region should be the next leader after the Muslim president died in office. Former president Yar'Adua had been expected to rule for another term, before his death left the presidency in the hands of a southerner. An unwritten agreement in the ruling party calls for its presidential candidates to rotate between the country's Christian south and Muslim north.
The explosions in Bauchi went off at three different locations and an unknown number of victims were critically injured, according to the police official. All roads leading to the Shadawanka Barracks were cordoned off by security personnel after the blasts.