A militant group in Nigeria is threatening to launch more attacks on the oil industry, a day after it seized four foreign oil workers. Gilbert da Costa in Abuja reports for VOA that Nigerian officials say they have established contact with the kidnappers.
 

Militants wearing black masks, military fatigues and carrying Kalashnikov assault rifles and rocket-propelled grenade launchers patrol the creeks of the Niger Delta area of Nigeria

Security officials have intensified their efforts to secure the release of the four kidnapped oil workers in the Bayelsa region. Militants of the Movement for the Emancipation of the Niger Delta, known as MEND, claimed responsibility for Thursday's attack.

Joshua Benamasia, who heads the Bayelsa state-sponsored group that monitors attacks on the oil industry, says contact has been established with the kidnappers.

"We have made contact," he said. "They say they will get back to us. We have gotten phone contact. We've also been able to realize that the people [hostage-takers] are in Rivers state, in the Kalabari area of Rivers state."
 
At least one person was killed in the shootout at an offshore oil facility early Thursday. MEND says it will launch further attacks on Nigeria's oil industry in the coming days.
 
Sam Oyadonho, a journalist in Bayelsa, says the group is responsible for other attacks.

"It is still the same state of fear, because nobody is sure where the next attack will come from," he said.  "Nobody is sure. Like what one of the survivors, one of the ladies that was injured at the farm tank, that the boys, they were eight in number, they torched all the vehicles, they burnt everything and took off again with their hostages."

Violence in the region has reduced oil output by at least 500,000 barrels per day in the world's eighth largest exporter, since February.
 
The latest attack comes six days before a meeting of Organization of the Petroleum Exporting Countries' (OPEC) ministers scheduled for Abuja, the Nigerian capital.