U.S. oil company Chevron is to suspend export contracts for much of its Nigerian output after an attack a key pipeline last week.
In a statement Chevron said it will invoke the "force majeure" clause, excusing the company from its contracts until December 31.
Force majeure is a legal term, relating to events beyond a company's control that prevent it from meeting contractual obligations.
Last Friday, militants in southern Nigeria attacked a Chevron pipeline that feeds into the Escravos terminal. The company says the attack reduced oil production by about 90,000 barrels a day.