Nigeria's main militant group, the Movement for the Emancipation of the Niger Delta (MEND) on Tuesday said it was responsible for the attack on the Exxon Mobil oil facility in oil rich Akwa Ibom state, as seven local employees were abducted.

Jomo Gbomo, the spokesperson for the group, said in an email statement reaching?Lagos that its fighters detonated explosives they had earlier rigged to the facility, causing considerable damage.

Exxon Mobil, in a statement sent to Xinhua on Monday said one of its offshore facilities was boarded by unknown armed persons in the evening of Sunday.

The attack came seven days after the London-Based oil exploration firm Afren said gunmen attacked its offshore oil rig and abducted seven crew members.

"The Movement for the Emancipation of the Niger Delta (MEND) confirms the attack on the Exxon Mobil Ibeno oil facility in Akwa Ibom state, in the Niger Delta, was carried out by its fighters," the statement said.

"The attack commenced at approximately 2040hrs Nigerian time and terminated at approximately 2237hrs Nigerian time after our fighters detonated explosives they had earlier rigged to this facility, causing considerable damage," MEND added.

"Like in the previous attack, on the Shallow-water okoro oilfield on Nov 7, 2010 , 7 local employees were abducted," the statement said.

"They were taken to prevent the Nigerian government from attributing the damage to this facility to an industrial accident, " it added.