Naiobi/Abuja - Nigeria's main militant group said Monday it had destroyed three oil facilities belonging to Chevron as it continued stepped-up operations against oil companies in the Niger Delta.

Movement for the Emancipation of the Niger Delta (MEND) spokesman Jomo Gbomo said in an emailed statement that militants had destroyed the Abiteye flow station and Abiteye Jacket 1 & 11 facilities in the early hours of Monday morning.

There was no immediate confirmation of the attacks, but Chevron on Saturday admitted that the militants had damaged another pipeline and facility in an earlier attack.

MEND called for "all-out war" on Nigerian forces in the Niger Delta last month after its camps were attacked.

Attacks on oil facilities and workers have cut oil production in Nigeria, one of the world's largest crude oil exporters, by around 20 per cent since 2006.

MEND and other groups operating in the Niger Delta said they are fighting for a larger share of the wealth from the oil-rich region for local residents, who complain the oil industry has ruined their agriculture and fishing livelihoods.

However, the government said the rebels are criminal gangs intent on stealing oil or making money through extortion.

The groups often kidnap expatriate workers, although MEND last week released Matthew Maguire, a British hostage it had been holding since late last year.(dpa)