LAGOS, Nigeria (CNN) -- A group of Nigerian rebels who wrote a letter to U.S. President George W. Bush, stating that they attacked two oil pipelines Monday, have asked for former President Jimmy Carter and actor George Clooney to help solve issues in the oil-rich Niger-delta.
Military policemen patrol the creeks of the Omadino community in Warri South district of the Niger Delta.
In a letter written by a group called Movement for the Emancipation of the Niger Delta, or MEND, the group said they attacked two pipelines they believed are owned by Chevron Corp. and Shell oil.
A spokesman for Royal Dutch Shell said its pipeline was damaged last week.
The attack will temporarily cut shipments by 169,000 barrels a day as workers try to repair the damage, the spokesman said.
The pipeline is owned jointly by Shell and Nigerian, French and Italian oil companies, the spokesman said.
Chevron spokesman Kurt Glaubitz told CNN that "No Chevron pipelines have been vandalized in Nigeria."
There was no immediate comment from the Nigerian government.
In the letter the group called themselves "commandos" and stated that their aim was "the crippling of the Nigerian oil export industry." Watch how Nigeria attacks help hike gas prices »
"Today's attack was prompted by the continuous injustice in the Niger Delta region of Nigeria where the root issues have not been addressed by the illegal and insincere government," the letter stated.
The letter stated that two other letters had been sent to Bush and also actor George Clooney, and the group also asked for President Jimmy Carter to help.
Clooney is one of the United Nations' Messengers of Peace, and has campaigned for an end to the long-standing conflict in Darfur, as well as further humanitarian relief efforts in the region.
Carter is currently in the Middle East, where he has met with the exiled militant Hamas leader Khalid Meshaal, on what he calls a "study mission" to support peace, democracy, and human rights in the region.
"MEND is prepared for talks and will prefer Ex President Jimmy Carter to mediate. Mr. Carter is not in denial as the rest of you who brand freedom fighters as terrorists," the letter stated. "The ripple effect of this attack will touch your economy and people one way or the other and hope we now have your attention."
The organization also said they attack was in response to one of the arrest of one of their members, Henry Okah, who was arrested last year and according to local reports, is charged with treason.
Since late 2005, MEND militants have carried out numerous attacks on Nigeria's oil sector and abducted dozens of foreign workers, releasing nearly all of them unharmed.
In the past the organization has said it had ratcheted up its attacks to redress what it says is the unequal distribution of the nation's oil wealth. E-mail to a friend