Naiobi/Abuja - Nigeria's main militant group said Thursday it had destroyed a major crude oil pipeline owned by Royal Dutch Shell, as it seeks to cripple Nigeria's oil and gas export industry.

The Movement for the Emancipation of the Niger Delta (MEND) has stepped up attacks against oil facilities in the oil-producing Niger Delta since Nigerian forces attacked one of its camps last month.

"Fighters ... destroyed with high explosives a major crude oil trunk line in Bayelsa state belonging to Shell," MEND spokesman Jomo Gbomo said in an emailed statement. "This delivery line ... supplies the Forcados export terminal."

There was no immediate confirmation of the attack, which MEND said was in response to the extrajudicial killing of two brothers by the Joint Task Force, which is responsible for protecting oil workers and facilities in the Niger Delta.

Independent human rights bodies have accused Nigerian forces of extrajudicial killings and of indiscriminately bombing villages in its campaign against MEND.

Attacks on oil facilities and workers have cut oil production in Nigeria, one of the world's largest crude oil exporters, by around 20 per cent since 2006.

MEND and other groups operating in the Niger Delta said they are fighting for a larger share of the wealth for local residents, who complain the oil industry has ruined their agriculture and fishing livelihoods.

However, the government said the rebels are criminal gangs intent on stealing oil or making money through extortion. (dpa)