Nigeria marks 50 years of freedom
Nigeria's president has led Africa's most populous country in celebrations to mark 50 years since independence from the UK.
"Our troubles and our failures are well catalogued," Goodluck Jonathan said about the shortcomings of the last half century.
During the ceremony, two blasts were heard in Abuja after a threat by oil militants. Police are investigating.
A BBC reporter at the celebrations says they have not been affected.
The BBC's Chris Ewokor says no explosions were heard at Eagle Square, where the parade is under way.
According to the AP news agency, two car bombs exploded in front of the federal high court in the capital, leaving three people injured.
The Movement for the Emancipation of the Niger Delta (Mend), a militant group in the oil-rich south, issued a threat on Friday morning saying it intended to bomb the event.
In the message, the group which is demanding a fairer distribution of the country's oil revenues, said that there was "nothing worth celebrating after 50 years of failure".
If Mend are responsible for the blasts, it would be the first time that the group has targeted the capital.
An amnesty for oil militants came into effect in the Delta last year, reducing the amount of kidnappings and unrest that has destabilised the region in recent years.
Nigeria is a major oil producer yet most of its 150 million people live in poverty.
Correspondents say more than 200 different ethnic groups co-exist in an uneasy coalition and the scars of numerous coups and a civil war are still visible.
"For a country that was intent on development on a similar if not better level with many countries at independence, it is discomforting that we are lagging behind, as economic indices among nations now show," Mr Jonathan said in his nationwide address.
Earlier, a former military leader, Yakubu Gowon, told the BBC that despite its faults and inner problems Nigeria was moving forward.
Three hot air balloons in the Nigerian colours of green and white have been flying above Eagle Square and an air force fly-past is expected as part of the festivities.
A number of heads of state from other African countries and representatives from countries around the world have arrived for the events.
In Lagos, the former capital where the handover from colonial rule took place 50 years ago, some buildings are draped in Nigerian flags.
The BBC's Caroline Duffield says busloads of schoolchildren have arrived in Tafawa Balewa Square in the centre of Lagos.
She says the ceremony will be slightly lower key than in 1960 with the national guard parading before the Lagos state governor and his royal highness, the Oba of Lagos, the traditional king, and other dignitaries.
But across Lagos, outside the square the mood is quiet, as many people appear to being taking advantage of the public holiday to leave the city to visit families, she says.