Nigeria's main militant group, the Movement for the Emancipation of the Niger Delta (MEND), has threatened to resume hostilities in the oil rich Niger Delta region by Jan. 20.

Jomo Gbomo, the group's spokesman, made the threat in a statement reaching in Lagos on Monday, saying it was reviewing its indefinite ceasefire announced on Oct. 9.

The group commended the youth that blew up a Chevron Makaraba pipeline in southeast Delta State on Friday in protest against the killings of three contract workers.

"This attack was sanctioned by MEND, but did not involve our fighters. The attack exposes the continued vulnerability of the oil industry infrastructure and the resolve of the people of the Niger Delta to fight for their land," the statement said.

The group has launched several attacks on international oil facilities in southern Nigeria as part of its campaign to get what it calls a fairer distribution of the region's oil wealth to local people.

In June, the Nigerian government offered amnesty to gunmen in the oil rich Niger Delta region, urging them to lay down their weapons by Oct. 4 in a bid to end unrest, which has cost Africa's top oil exporter billions of dollars in lost revenue.

Scores of Nigerian armed youth gave up their weapons and embrace amnesty offered by the Nigerian government in the most concerted effort yet to end years of fighting in the oil-rich producing region.

The Niger Delta is an unstable area where inter-ethnic clashes are commonplace. Access to oil revenue is the trigger for the violence.

Over 300 foreigners have been seized in the Niger Delta since 2006. Almost all have been released unharmed after paying a ransom.