UPDATE 2-Nigeria militants say attack Chevron oil manifold

* Militants say attack Chevron pipeline junction point

* Second attack on Nigeria oil sector in as many days

* Violence cuts at least 273,000 bpd of oil output

(Adds Chevron spokesman, background)

By Randy Fabi

ABUJA, July 6 (Reuters) - Nigeria's main militant group said on Monday it had sabotaged one of Chevron's (CVX.N: Quote, Profile, Research) crude oil pipeline junction points in the Niger Delta, the second attack in as many days.

The Movement for the Emancipation of the Niger Delta (MEND) said it attacked Chevron's Okan manifold late on Sunday in the southern Delta state, hours after it sabotaged an oil well head operated by Royal Dutch Shell (RDSa.L: Quote, Profile, Research).

"The strategic Okan manifold ... was blown up at about 2045 hours on Sunday," the militant group said.

It was not immediately possible to independently verify the statement.