Nigeria's main militant group says it has attacked major oil pipelines in the oil-rich Niger Delta, preventing five flow-stations from feeding Chevron tanks.
The Movement for the Emancipation of the Niger Delta, or MEND, said (in a statement) Monday that the out-of-operation stations are Alero Creek, Otunana, Abiteye, Makaraba, and Dibi.
There was no immediate confirmation from Chevron.
The attack on the pipelines comes as the Nigerian military expands its operation against the rebels in the oil-rich south.
Sunday Nigerian soldiers rescued three Filipino hostages being held by rebels.
The Nigerian state minister for petroleum said recently that three-and-a-half years of violence in the Niger Delta has reduced Nigeria's oil production to less than half of its total capacity.
Niger Delta militant groups began a campaign against the government in 2006. MEND, the largest of the groups, says it wants more of the region's oil wealth directed to impoverished local residents
The Nigerian government dismisses the militants as criminals.
Some information for this report was provided by AFP and Reuters.