An explosion has damaged a major oil pipeline in southern Nigeria, causing an oil spill and and a large fire.

Reuters news agency quotes a local official who says eight people have been killed, though that report has not been independently confirmed.

Oil company Shell, which operates the pipeline, says the fire may have been caused by a dynamite attack carried out by unknown assailants.

The blast occurred near the oil center of Port Harcourt. Shell says it has closed two oil fields that feed the pipeline in order to help curb the fire.

The company says the explosion will at least temporarily cut Nigerian crude oil production by 170,000 barrels per day. The total amounts to about seven percent of Nigeria's daily output.

Some information for this report provided by AFP and Reuters.