NAIROBI (Reuters) -A revenge attack triggered by a cattle raid earlier this month has killed at least 17 people in northern South Sudan and forced oil workers to evacuate from the Toma South oil field, a local official said on Monday.

Cattle raiding linked to competition for scarce resources is one of the main triggers of conflict between ethnic groups in South Sudan, which is awash with weapons after decades of war.

The fighting began on Saturday in a Khat Elnar village in the Ruweng Administrative Area, where government officials were trying to resolve issues over a previous cattle raid, said James Arop Ayuel, a local government spokesperson.

The violence spread to the Toma South oil fields, which are managed by Greater Pioneer Operating Company (GPOC), where a facility was attacked and looted, Ayuel said.

"We are calling for the government of South Sudan to bring forces so that they protect the oil fields because this is a national issue," Ayuel said.

"They went and looted the oil fields facilities. Up to now, as I'm talking, this morning I was told they came over the night and looted the compound again," he said.

The heavily armed raiders came from Rubkona County of neighbouring Unity State to reclaim cattle stolen by youth from Ruweng Administrative Area, Ayuel said.

Cattle are an important indicator of wealth and status in South Sudan, and are usually given as a bride price to a woman's family as gifts ranging from fewer than 10 to several hundred.

(Reporting by Nairobi Newsroom; Writing by Hereward HollandEditing by Ros Russell and Leslie Adler)