Nigeria's main militant group said its fighters sabotaged a Royal Dutch Shell oil pipeline in the southern Niger Delta on Thursday, the latest in a string of attacks against Africa's biggest energy producer, according to Reuters. The Movement for the Emancipation of the Niger Delta (MEND) said in an e-mailed statement it had attacked the Billie/Krakama pipeline in Rivers state in the Niger Delta. Attacks from MEND have forced foreign oil companies, including U.S. oil major Chevron and Italy's Agip, to shut at least 133,000 barrels per day of oil production in the past month. MEND said the damaged pipeline it attacked on Thursday fed into pumping stations connected to the Bonny crude oil terminal, one of Nigeria's main export terminals. A Shell spokeswoman said the company had shut down one of its pipeline junction points, but declined to say whether any oil production was affected. "The facility has been shut down and an emergency team has been mobilised to limit the environmental impact," she said. The latest attack in the world's eighth largest crude oil exporter helped push oil prices up near $69 on Thursday. On Sunday, MEND claimed responsibility for attacks on three Shell installations, including the Afremo offshore oilfields. Shell said it was investigating those attacks and was carrying out aerial inspections to try to assess any impact on output or the extent of any environmental damage from potential spillage.