WARRI, Nigeria (AP) — Nigerian militants say they have bombed an oil export pipeline operated by U.S.-based multinational Chevron, and are warning companies not to carry out repairs to sabotaged infrastructure that has reduced oil exports from this West African nation to a near 30-year low.

The Niger Delta Avengers say they "took down" Chevron's 100,000 barrel-a-day offshore pipeline at Escravos early Tuesday. That breaks a 3-month cease-fire days before President Muhammadu Buhari is expected for peace talks in the southern oil-producing region.

The warning against repairs comes as British-Dutch multinational Shell prepares to resume exports eight months after the Avengers bombed an undersea pipeline and halted exports from Shell's 250,000 barrel-a-day Forcados terminal. The International Energy Agency estimates the Forcados closure lost Nigeria $1 billion in just three months.