Nigeria's state-run oil company said late Monday that no new crude production had been shut despite a wave of militant attacks on energy infrastructure in recent days.

State-owned Nigerian National Petroleum Corp. has joint-venture partnerships with major oil companies, such as Royal Dutch Shell PLC (RDSA), the largest foreign operator, and Chevron Corp. (CVX), in the Niger Delta.

Militants seeking a greater share of Nigeria's oil wealth for local people Sunday said they had sabotaged two recently repaired oil pipelines in reprisals for an army attack against one of their camps.

The army said a pipeline supplying state-owned Nigerian Gas Co. had been blown up but with no impact on supply.

Chevron over the weekend said its operations continued as normal. But Shell reiterated Monday it is investigating a report that one of its facilities was attacked.

Unrest in the region has reduced Nigeria's daily output to 1.76 million barrels, compared with 2.6 million barrels in January 2006.

-By Spencer Swartz and Benoit Faucon, Dow Jones Newswires; +44 (0)207 842 9357; spencer.swartz@dowjones.com