ABUJA Car bomb explosions killed eight people and injured three near a parade in Nigeria's capital on Friday marking the 50th anniversary of independence, police said.
Two blasts, which also destroyed three cars, came an hour after the Movement for the Emancipation of the Niger Delta (MEND), Nigeria's biggest rebel militia, warned it had planted several bombs and told people to evacuate the area.
A Reuters cameraman said security forces and firemen in the capital, Abuja, had been dousing a fire in a car after the first explosion when a second blast hit, about 1 km (half a mile) from the parade ground where hundreds of Nigerian and foreign dignitaries sat.
"Two car bombs exploded and eight people are confirmed dead," Abuja police spokesman Jimoh Moshood told Reuters.
The lavish celebrations with army bands, dancing children and air force displays continued unabated, with President Goodluck Jonathan, who faces an election early next year, arriving in an armoured limousine shortly after the bomb threat.
After his departure, his office issued a statement condemning the attack as a "dirty and wicked act" and vowing to bring its perpetrators to justice.
"To those behind these vicious acts, the president wants you to know that you will be found, and you will pay dearly for this heinous crime," the statement said.
MEND has been fighting for years for a greater share of oil revenues from the impoverished Niger Delta, home to Africa's biggest oil and gas industry.
Although most of its activities have been focused on the creeks and swamps of the delta, MEND has struck further afield, including at off-shore oil installations and in the heart of Nigeria's commercial capital, Lagos.
"Several explosive devices have been successfully planted in and around the venue by our operatives working inside the government security services," the warning email, signed by MEND spokesman Jomo Gbomo, said.
"In evacuating the area, keep a safe distance from vehicles and trash bins."
Besides overshadowing the 50th birthday of Africa's most populous nation, the bombs could deal another blow to an already a shaky amnesty brokered last year with rebels in the Delta.
Nigeria's oil production has climbed from about 1.6 million barrels per day before the amnesty to around 2 million now, as oil companies have been able to repair sabotaged pipelines and supply terminals.
A return to violence would be likely to reverse those gains, with implications for Nigeria's wider economic growth, although security analysts said major MEND attacks have not necessarily been followed by a spike in oil-related violence.
"It's a big event in itself because they've killed a reasonable number of people, but I don't think it will have much aftermath," said Peter Sharwood-Smith, country manager for security consultancy Drum-Cussac.
"MEND have always taken advantage of any kind of event that will have the world's attention to get their point across."
Jonathan is from the Niger Delta area, and many analysts thought his accession to the presidency earlier this year after the death of president Umaru Yar'Adua would have eased tensions between rebels and central government.
Despite the official pomp, the 50-year landmark has caused considerable introspection among Nigeria's 140 million people, many of whom regard the period since the end of British rule in 1960 as a half-century of broken dreams.
As well as a succession of brutal and economically disastrous military dictatorships and the squandering of billions of dollars in oil revenues, Nigeria suffered a civil war in the late 1960s in which a million people died.
"Leadership has failed the nation again and again and again," said author Wole Soyinka, the first African to win the Nobel Prize for Literature, describing the post-colonial era as a "wasted generation."
"It has been backwards steps -- one step forwards and then ten back."
Despite the gloom, others feel that, after 10 years of unbroken civilian rule, Nigeria is on the cusp of a major revival, supported by high oil prices, a flood of foreign investment and the gradual liberalisation of its economy.
(Additional reporting by Camillus Eboh and Nick Tattersall, writing by Ed Cropley; editing by Giles Elgood)