A car bomb attack on a Nigerian army barracks killed two civilians and seriously injured six more in Port Harcourt, the capital of Africa's biggest oil industry, officials said on Thursday.
Militants fighting to control the Niger Delta's huge oil reserves claimed responsibility for the blast and warned of more attacks, piling pressure on energy markets that are already nervous about Iran's nuclear standoff with the West.
"The incident happened between 8:00pm and 8:30pm yesterday [Wednesday]. A Mercedes Benz car that was passing through the barracks exploded. One person died instantly, while a second person died this morning [Thursday]," said Major Musa Sagir.
"Six other people were injured and are receiving treatment. No soldier was involved. All the victims were civilians. It is still not clear if the substance was a bomb or dynamite," said the spokesman for the 2nd Amphibious Brigade.
National police spokesman Haz Iwendi described the explosion as a "bomb blast," and said detectives and military intelligence were investigating.
Port Harcourt is the hub of Nigeria's oil industry and threats of further militant violence there will put more pressure on world crude prices.
"It was a car bomb fitted in a Mercedes Benz 200, 1980 model," a spokesman for an outlawed militant group, the Movement for the Emancipation of the Niger Delta (MEND), said in response to an e-mail query.
If Wednesday's blast is confirmed to have been a remotely detonated device, it would be be the first such attack by the delta militants. They have previously confined themselves to guerrilla assaults and kidnappings in the delta swamps.
"This was intended as a warning to the Nigerian government and oil companies," the anonymous MEND spokesman added.
"The driver and other occupant left the scene long before this device was activated by cellphone. I assure you, all our operatives involved in this operation are home and dry," he said.
"In the coming weeks, we will carry out similar attacks against relevant oil industry targets and individuals. We have proved continuously that the Nigerian military is incapable of protecting itself, let alone oil industry workers," the spokesman said.
Bori Camp is close to the center of Port Harcourt, a sprawling riverside city which is the Nigerian base of several international oil firms. Civilian traffic is usually allowed to use a road through the base.