FACTBOX-Which oil firms are affected by Niger Delta unrest?

July 5 (Reuters) - Nigerian militants said on Sunday they had launched their third attack against Royal Dutch Shell (RDSa.L: Quote, Profile, Research) since President Umaru Yar'Adua made an amnesty offer and warned their campaign of sabotage would intensify.

Following are details on which firms have been affected by MEND's latest campaign and what they have said about production:

CHEVRON CXV.N

The U.S. energy firm said on May 25 it had shut in approximately 100,000 barrels per day (bpd) of oil production from its swamp operations in Delta state following the first major strike in the militants' latest campaign. [ID:nLP693007]

The Movement for the Emancipation of the Niger Delta (MEND) said that day it had sabotaged pipelines to flow stations at Alero Creek, Otunana, Abiteye, Makaraba and Dibi in Delta state.

MEND claimed on June 10 to have sabotaged Chevron's Otunana pumping station in Delta state but the military denied any such attack had occurred and that a fire at the facility, confirmed by Chevron, was a result of a systems failure. [ID:nLA242679]

On June 13, Chevron confirmed there was a breach on its Makaraba-Utonana-Abiteye pipeline and fire at its Makaraba Jacket 5 facility in Delta state but said output was unaffected as the infrastructure had already been shut down.

MEND said on June 15 it had attacked Chevron's Abiteye flow station. [ID:nLF222833]