Nigeria's high-profile armed group, the Movement for the Emancipation of the Niger Delta, or MEND, has claimed responsibility for Thursday's attack on a vital oil pipeline in the troubled oil-rich Niger Delta. MEND has staged a string of attacks and kidnappings on oil facilities since 2005. Gilbert da Costa in Abuja reports renewed violence could dash hopes of a government peace campaign.

In an e-mail statement sent to journalists late Thursday, the Movement for the Emancipation of the Niger Delta said the early morning attack was carried out by a small commando unit. The group said it plans to attack non-oil targets such as bridges and other basic infrastructure across the country.

It was the second raid in a week. A facility belonging to the American oil giant, Exxon Mobil, was also attacked Tuesday.

Analysts see the resurgence of violence as a setback for the new administration's peace initiatives in the region.

ThankGod Subbi, a militant leader in the delta who supports peace talks with the authorities, urged the government to deliver quickly on its promises to the region.

"There is relative peace now," he said. "There is nothing to worry about. The government should keep their promises to the people of the region. They should hasten up to do some of the things, practically, so that the people will have confidence in them."

The damaged pipeline feeds the Forcados export terminal. Reports suggest the attack may have cut off production of about 50,000 barrels per day of oil.

Production had just been restored at the facility operated by Royal Dutch Shell after an earlier wave of attacks and kidnappings in 2006 forced its closure.

Violence has surged across the Niger Delta since the arrest of a MEND factional leader in Angola. The group says it is fighting for more local control of the delta's oil wealth.

Thousands of workers have been forced to leave the region, cutting oil output from Nigeria, the world's eighth largest exporter, by more than 20 percent.

President Umaru Yar'Adua came to power in May promising urgent steps to bring peace to the region, where anger over neglect and underdevelopment runs very deep.