Feb 7, LAGOS, Nigeria _ The Nigerian military says it has repelled a rebel attack on a natural gas production plant in the country´s southern petroleum-producing region.The region´s main militant group, the Movement for the Emancipation of the Niger Delta, claimed responsibility for the attack.It was launched a week after the group called off a self-declared months-long ceasefire.A Nigerian military spokesman says the attackers were prevented from entering the facility in Delta state.He say three attackers were killed and one soldier was wounded.The rebels denied suffering any casualties.Anglo-Dutch oil giant Royal Dutch Shell PLC confirmed an incident at the facility run by its local unit at Utorogu. The company said one employee and two contractors were wounded in the attack, but all three had been treated and were in stable condition.Shell did not say if the attack halted production.Saturday´s gun battle was the latest in nearly three years of violence in the southern Niger Delta, strife that has slashed output from Africa´s biggest oil producer. Oil-industry workers are regularly kidnapped for ransom and energy facilities and transport ships are often attacked.Amid the tensions, Nigeria´s oil output has sunk to about 1.8 million barrels a day, or about 25 per cent less than its capacity of 2.5 million barrels.The militants say they are battling to force the federal government to send more oil-industry funds to the southern region, which remains deeply poor despite its great natural bounty.The government says the militants are organized criminals engaging in the lucrative overseas trade in crude oil by illegally tapping Nigeria´s vast pipeline network.