A Royal Dutch Shell pipeline was blown off on Monday as Nigerian militants carried out another attack. The oil company was forced to cut its production and help keep world oil prices near record highs.

The militant attacks have grown in number and their aim is mainly to cut the country’s oil output. The attacks have cut the 2006 production by about 20% in Nigeria, the world’s eighth-largest oil producer and the 4th-largest supplier to the United States

The rebels reportedly attacked while Shell was working to fix the damage made by similar attacks carried out last month.

Some oil had spilled from the company’s Nembe Creek trunk line, which takes crude to the export terminal in Bonny.

"An overfly this morning showed some oil had spilled into the environment and we have mobilized equipment to contain further spread of oil. We have also shut in some production to stop further spill," the British-Dutch company said in a statement.

The responsibility for the attack was taken shortly after it was carried out by the Movement for the Emancipation of the Niger Delta (MEND) through an e-mail. There are many other rebel groups that fight to control the local oil. The last attack was aimed against the government of President Umaru Yar'Adua, the MEND said when they claimed it.

"Today's attack is dedicated to the administration of Umaru Yar'Adua and (Vice-President) Goodluck Jonathan who have failed after one year in office to ensure peace, security and reconciliation in the Niger Delta," MEND said.