The Movement for the Emancipation of the Niger Delta (Mend) said in a statement its fighters had destroyed two of Chevron's oil wells at Makaraba and the Otunana oil well in Nigeria's southern Delta state.

A Chevron spokesman said it was investigating the claims and that 'we are working to ensure the safety of our people, restore the integrity of our operations as soon as possible.'

The company confirmed earlier Saturday that a Mend attack the previous day had damaged oil and gas pipelines.

A Mend attack last month knocked out a Chevron pipeline, forcing a 100,000 barrel-per-day oil output cut, over one quarter of the company's Nigerian production.

Mend, which has staged numerous attacks on international oil facilities in southern Nigeria as part of its campaign to get what it calls a fairer distribution of the region's oil wealth to local people, declared last weekend a new campaign against oil companies.

On Friday the group released a British oil sector worker who had been held for nine months.

Nigeria's oil production has been cut by more than a quarter because of the militant campaign over the past three years, allowing Angola to catch up and compete with it for the position of Africa's top oil producer. -- AFP