LAGOS, Dec. 19 (Xinhua) -- The Movement for the Emancipation of the Niger Delta (MEND) has claimed the explosion which was carried out on Saturday on a major Shell/Chevron crude pipeline in southern Rivers State.

The strike which came as a warning was carried out by five boats involving 35 fighters armed with assault rifles, rocket launchers and heavy caliber machine guns.

The MEND disclosed in an e-mail sent to media organizations that the attack was carried out for the following reasons: The Nigerian government has conveniently tied the advancement of talks on the demands of this group to a sick president but it has not tied the repair of pipelines, exploitation of oil and gas as well as the deployment and re-tooling of troops in the region to the presidents ill health.

A situation where the future of the Niger Delta is tied to the health and well being of the president is unacceptable, the group said.

The statement added that the MEND is committed to continuing its fight for the restoration of the land and rights of the people of the Niger Delta and the indefinite ceasefire ordered by the group on October 25 will be reviewed within 30 days from this Saturday.

Sources confirmed that the strike which came after a two-month truce on strikes on oil installations by militants was targeted at a Shell/Chevron crude pipeline in Abonemma, Rivers state of Nigeria.

Analysts said that it is not a good sign for the amnesty program of the Nigerian government, which has achieved remarkable progress in the past two months.

The Nigerian government offered an amnesty to gunmen this June in the oil-rich Niger Delta region, urging them to lay down their weapons by Oct. 4 in a bid to end the unrest which has cost the African top oil exporter billions of dollars in revenue.

Over 8,000 Nigerian armed youths gave up their weapons and embraced the amnesty offered by the Nigerian government in the most concerted effort yet to end years of fighting in the oil-rich producing region.

The success of the amnesty and disarmament policy spawned immediate results recently when the Nigerian National Petroleum Corporation announced that the country's crude production per day had risen to 2.4 million barrels, including condensates, since relative peace returned to the Niger Delta.

Nigerian President Umaru Yar'Adua fell ill and left for Saudi Arabia for treatment on Nov. 24, which has delayed major progress in the implementation of post-amnesty programs.