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

July 10 (Reuters) - Nigeria's main militant group said on Friday it attacked an oil pipeline recently repaired by U.S. oil major Chevron (CVX.N) in the Niger Delta.

A total of around 300,000 barrels per day of Nigeria's oil output has been shut down since MEND launched its latest campaign of violence in late May.

Following are details on which firms have been affected and what they have said about production:

CHEVRON CXV.N

The Movement for the Emancipation of the Niger Delta (MEND) said on July 10 it attacked a recently repaired oil pipeline linking Alero creek through Abiteye to Chevron's export terminal in Delta state. [ID:nLA437845]

The militant group said on July 6 it attacked Chevron's Okan manifold in southern Delta state. [ID:nL627910]

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]

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]

ROYAL DUTCH SHELL (RDSa.L)

Shell has said the latest attacks have slashed output from its onshore facilities to 140,000 barrels per day (bpd), around half of what it was producing earlier this year. [ID:nLU240107]

MEND said on July 8 it had attacked Shell's Nembe creek oil pipeline at Asawo village in Bayelsa state.

The militant group said on July 5 it had attacked a Shell oil well head in the Cawthorne Channel which is connected to the Bonny export terminal in Rivers state. Shell said no output was affected.