Nigeria's best-known militant group, the Movement for the Emancipation of the Niger Delta, is claiming responsibility for attacking a facility run by the Italian oil firm Agip.
In a written statement, the group says it is launching a new campaign of attacks ahead of April's legislative, presidential, and gubernatorial elections as a reminder to the government not to take its threats for granted. The group is warning Nigerians to stay away from political gatherings.
Smoke and debris fill the sky after a car bomb explodes alongside firemen responding to an initial car bomb that had exploded five minutes earlier in Abuja, Oct 1 2010
These militants claim responsibility for bombings last October near Independence Day celebrations in the capital Abuja that killed 15 people.
There have already been a series of bombings at campaign events in the oil-rich Niger Delta as well as attacks against candidates in northern Nigeria, where a separate militant group says it is fighting to establish an Islamic state.
With more than 70 million Nigerians registered to take part in April's vote, security services in Africa's most populous nation say they are taking unprecedented measures to ensure a safe election.
Chukwuemeka Ebuka, assistant to the secretary of police for Anambra State, says the "readiness on the side of the police is to ensure that the election is free and fair and to ensure that any violent act is nipped in the bud."
There have been problems in the past with Nigerian militants disguised as security forces. Ebuka says there will be special tags to identify policemen involved in securing the vote.
"So that will make it impossible for anybody who is a fake policeman. It will make it easier for real and genuine policemen to identify the fake ones," said Ebuka.
Delta State University political science professor Benjamin Agah says the government's primary responsibility here is ensuring proper security for a free and fair vote. He says politicians themselves are to blame for some of the violence as elected office in Nigeria has become a make-or-break grab for money and power.
"Politics is not a do-or-die affair. Politics is to serve the people," said Agah. "So the moment the people you are going to serve say no to you, don't go."
Retired Rear Admiral John Kpokpogri is running for deputy governor of Delta State as the candidate of the opposition Action Congress of Nigeria party. He agrees there is a sometimes desperate, winner-take-all mentality to Nigerian politics.
"It is not a do-or-die affair. We go and play the game according to the rules, and the more popular candidate will win at the end of the day," said Kpokpogri. "I believe that the democracy, the election is going to be free and fair."
Kpokpogri says he is satisfied with the government's response to electoral violence thus far.
"The violence or those issues have nothing to do with the election. The election is going to take place, and the security agencies are equal to any miscreants who are trying to cause problems that people think will ruin the election,"Kpokpogri said. "The election is going to come and take place and nothing negative will happen."
This will be the fourth presidential election since Nigeria's return to civilian rule in 1999. President Goodluck Jonathan is facing several challengers, chief among them former military ruler Muhammadu Buhari.