Lagos, Nigeria (CNN)  -- A previously unknown armed group said Friday it attacked a Nigerian oil pipeline this week on the first full day in office for Nigeria's new acting president.





The attempt by the Joint Revolutionary Council (JRC) of the Niger Delta was not successful, a spokesman for the military said. But it indicates not everyone in Nigeria is happy with the way the new president, who hails from the Niger Delta region, was given power.





The JRC said that early Wednesday, one of its units attacked and "exploded" the Tura manifold owned by Royal Dutch Shell in Abonnema, near the coast. The manifold connects several pipelines to the Bonny Export Terminal.





"Our patriotic fighters fought and overpowered the military guards on duty (as all Shell manifolds are always heavily guarded) before going ahead to explode the Tura manifold," the group's statement said.





But Lt. Col. Timothy Antigua, a spokesman for the Nigerian military, said the attack failed.





"On Wednesday night there was an attempt by criminals to sabotage a Shell pipeline," he told CNN. "They were thwarted in their attempt by a community surveillance group assigned to protect the Shell pipeline."





Antigua said the group's dynamite and other explosives were recovered and that there were no injuries or deaths.





A spokesman for Shell in The Hague, Netherlands, said the company had received no report of an attack.





The JRC said its attack Wednesday followed another last weekend, and that both are aimed at incapacitating the export terminal and fighting the "occupation" in Nigeria.





"The actions are continuous and are preparatory to the final war. Every little step we take today brings us closer to freedom," read the statement.





Acting President Goodluck Jonathan was approved for the role Tuesday by Nigeria's House and Senate to fill the political void left after President Umaru Musa Yar'Adua departed in November for medical treatment in Saudi Arabia.





Jonathan was previously the country's vice president.





In his first address to the nation Tuesday, Jonathan praised the "resilience and unity of purpose" with which Nigerians reacted to the recent political upheaval, saying there were "no winners and no losers" and that it is now time to move forward.





He called on all Nigerians and the country's political parties to "tackle the various challenges which we face as a nation," including those in the areas of power, infrastructure, security and job creation.





Jonathan also vowed to pursue the "war against corruption" more robustly.





His appointment has stirred controversy in Nigeria, Africa's most populous nation, with some arguing that the articles of the Nigerian constitution were not followed with the transfer of power.





Nigeria's constitution says the president must formally communicate to the National Assembly that he is empowering the vice president to act as president in his absence.





While no such formal communication was given, the Senate declared Tuesday that a January 13 BBC interview with Yar'Adua from his hospital bed could constitute such a notice.





In the interview, the president acknowledged that he could not perform the duties of his office and would not be able to return until his doctors declared him fit.





In a separate statement, the JRC called Jonathan a "lame-duck ruler" and termed his acting presidency an "illegality" because of questions over the transfer of power. The group said Jonathan was appointed in a "jungle manner."





"The purported interview granted the British Broadcasting Corporation by the deserter president can never (be) approximated to a (formal)/official letter which ought to be duly endorsed by the writer," the JRC said. "The deserting act of Alhaji Umaru Musa Yar'Adua can only be appropriately categorized as gross misconduct and should naturally have attracted an impeachment. This ought to have been followed by the swearing in of the vice president as substantive president, not in an acting capacity."





The group said the political events will not deter their "resolve to wage a continuous revolutionary war to liberate all parts of our territory."





CNN's Christian Purefoy contributed to this report.
What did the Nigerian spokesman say about the attack? Who does Acting President Goodluck Jonathan replace? Who claimed the pipeline attack? Who is the acting President? Who was approved for the role? What did JCR say? Who is spokesman for Nigerian military?
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question: What did the Nigerian spokesman say about the attack?, answer: the | question: Who does Acting President Goodluck Jonathan replace?, answer: Umaru Musa Yar'Adua | question: Who claimed the pipeline attack?, answer: Joint Revolutionary Council (JRC) of the Niger Delta | question: Who is the acting President?, answer: Goodluck Jonathan | question: Who was approved for the role?, answer: Goodluck Jonathan | question: What did JCR say?, answer: one of its units attacked and "exploded" the Tura manifold | question: Who is spokesman for Nigerian military?, answer: Lt. Col. Timothy Antigua,