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 trying to douse a fire in a car after the first explosion when a second blast hit, about 1 km (0.6 miles) from the parade ground where hundreds of local 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 although President Goodluck Jonathan, who faces an election early next year, left in an armoured limousine without making a scheduled national address.
Earlier, Jonathan, dressed in his traditional black fedora hat and dark suit, had inspected ranks of soldiers from the back of an open-top jeep.
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 will 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 that process, with implications for Nigeria's economic growth.
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.
"A very sad and unwelcome development, when a small group of people from the same region as the President carry out such attacks on Nigeria's special day," said one Nigerian security expert, who did not wish to be named.
"These people do not reflect the wider feelings of Niger Deltans and such acts can only be fully condemned."
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 gradual liberalisation of its economy.
(Additional reporting by Camillus Eboh and Nick Tattersall, writing by Ed Cropley; editing by Philippa Fletcher)