The authorities in Nigeria's southern Delta State have asked the international oil company, Shell, to clean up an oil spill which has caused widespread environmental damage.

The spill from an oil well in the Ugheli area near the town of Warri has led to thousands of barrels of crude oil spreading to rivers and farmland.

A Shell spokesman told the BBC the company was considering the request but felt aggrieved because it had been caused by an act of sabotage.

The BBC Nigeria correspondent says Shell has been involved in an acrimonious dispute with communities in the southern Delta region.

He says saboteurs damage oil installations with the hope that they will be offered employment in the clean-up operation.

From the newsroom of the BBC World Service