In an emailed statement, Niger Delta Greenland Justice Mandate (NDGJM) spokesperson Aldo Agbalaja said "Opudo strike force, at about 23:30 on Sunday, September 18, 2016, struck the Afiesere-Ekiugbo delivery line in Ughelli, operated by NPDC/Shoreline."
The rebel group hit the same pipeline last Tuesday and vowed to "ground" the Nigerian economy, which is already in recession, in part due to plummeting oil exports as a result of sabotage.
Ratings agency Standard & Poor's cut Nigeria's credit rating last week, saying the "marked contraction" in oil production from an average of 2.1 million barrels per day to 1.7 was hurting its economic prospects.
The NDGJM has stepped up its attacks after rival group the Niger Delta Avengers declared a ceasefire in August and entered talks with the Nigerian government.
"All agrarian products in the area surrounding the scene of the incident have been damaged as a result of the blast," a resident of the nearby Ekuigbo community, Efemena Akposire, told AFP.
A military officer added: "Unlike previous attacks carried out by the group where they hack-sawed the pipelines, dynamite was used in this case."
Poor living conditions
Nigeria's military has boosted its presence in the oil-producing southern swamplands in response to the attacks, raiding suspected militant camps and clamping down on illegal oil refineries.
Various rebel groups have complained about poor living conditions in the area, where despite massive oil wealth most people live in poverty without access to basic services such as education and health care.
Distrust in the Nigerian security forces is widespread in the region. Last week the NDGJM complained of intimidation and vowed to "match force with the oppressor's brutality".
Rebel attacks are not the only crimes plaguing the region: kidnappings for ransom are also common.
Nigerian police said Monday it had rescued 14 local oil workers and their driver after a shoot-out with their kidnappers near the oil hub of Port Harcourt, capital of Rivers state.
The employees of Nestoil Plc, an oil and gas service firm, were seized on September 2 by a gang of men who hijacked their vehicle and fired shots into the air to frighten away bystanders.
Rivers police spokesman Nnamdi Omoni said none of the oil workers was injured and no ransom was paid. Efforts were being made to track down the kidnappers, he added.