UPDATE 1-Nigeria militants say attack Shell oil facility

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LAGOS, July 5 (Reuters) - Nigeria's main militant group said on Sunday it had attacked a Royal Dutch Shell (RDSa.L: Quote, Profile, Research) oil facility in the Niger Delta, its third such strike since President Umaru Yar'Adua made an amnesty offer last month.

The Movement for the Emancipation of the Niger Delta (MEND) said in an emailed statement it had attacked a Shell well head in the Cawthorne Channel at about 0300 hours (0200 GMT).

"The facility connects to the Bonny loading terminal in Rivers state," it said, referring to a key oil export terminal in the eastern part of the Niger Delta.

There was no immediate confirmation from Shell or from the military task force which patrols the Niger Delta.

Shell said on Tuesday that the latest attacks -- which had largely focused on the western Niger Delta -- 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]

Yar'Adua said 10 days ago he would offer a 60-day amnesty to gunmen to try to end unrest which has prevented Nigeria from pumping much above two thirds of its installed capacity since early 2006, costing it billions of dollars in lost revenue.

MEND blew up a Shell well head in Delta state hours after the amnesty proposal, accusing the military of going on a "punitive mission" to hunt down suspected militants despite the offer, a charge the security forces denied. [ID:LQ460625]

Fighters from the group also attacked two well clusters in Shell's Estuary field on Monday, forcing the Anglo-Dutch giant to shut in some production as a precaution. [ID:nLT318433] (For full Reuters Africa coverage and to have your say on the top issues, visit: af.reuters.com/ ) (Reporting by Nick Tattersall, editing by Elizabeth Fullerton)