Nigerian officials say militants attacked a major Chevron oil and gas facility and the U.S.-based multinational says it has shut production there but exports will continue.

A new group called the Niger Delta Avengers says it bombed the offshore Okan platform on Wednesday and warned international companies that "the Nigerian military can't protect your facilities."

Security forces launched an offensive this year after militants demanding a greater share of oil profits renewed attacks that forced the closure of two oil refineries and a major export terminal, aggravating fuel and power shortages.

Nigerian Navy spokesman Commodore Chris Ezekobe said Friday the attack occurred near Escravos terminal in the oil-rich south.

Chevron spokesman Deji Haastrup said the facility is shut down but would not say how much oil it was producing.