Delta Violence Timeline

Nigerian militants have attacked oil facilities in the Niger Delta in the heaviest fighting in two years.

The Movement for the Emancipation of the Niger Delta (MEND) is responsible for attacks that have cut a fifth of the OPEC member's output since it emerged late in 2005. Below is a chronology of conflict in the Niger Delta since then.

Dec 2005 - Dynamite attack on major pipeline operated by Royal Dutch Shell kills eight people. MEND claims responsibility.

Jan 2006 - Militants carry out a series of raids on oil installations, killing six people in a raid on a Shell platform and prompting the firm to evacuate hundreds of workers.

Feb 2006 - Nigerian forces attack targets in the Niger Delta by helicopter gunship and militants fire back with rockets as the conflict escalates.

Oct 2006 - Militants in speed boats attack soldiers escorting a convoy supplying oilfields, killing five. Days later, militants kill 17 soldiers in two separate gun battles.

June 2007 - After new President Umaru Yar'Adua takes office, a court frees former militia leader Mujahid Dokubo-Asari on bail. He had been in jail since 2005.

Sept 2007 - Suspected militant leader Henry Okah arrested in Angola, prompting MEND to pull out of talks. He was extradited to Nigeria to face treason charges in Feb. 2008.

Feb 2008 - A group of influential rebels and activists say they want to resume peace talks with the government but MEND stays out.

April 2008 - Angola temporarily surpasses Nigeria as Africa's top oil producer because of the Niger Delta outages.

June 2008 - MEND attacks Shell's Bonga oilfield, 120 km (75 miles) offshore, the furthest it has struck in Nigeria's deep waters.

July 2008 - Top U.N. official Ibrahim Gambari resigns as head of committee organising peace talks after Niger Delta leaders criticise his role under past dictator.

Sept. 10, 2008 - Yar'Adua approves creation of a new ministry for the Niger Delta, but militants are dismissive of the idea.

Sept 14, 2008 - MEND declare an "oil war" in the Niger Delta after two days of gunbattles with security forces.

(Reuters)