JUBA, Sudan – South Sudanese gunmen have killed up to 49 people from a rival tribe, most of them women and children, in one of a string of attacks that have raised fears for elections in the region, officials said on Monday.

Fighters from the Lou Nuer tribe raided the village of Torkeij, home to the Nuer Jikany, in the region's Upper Nile state on Friday, in apparent revenge for cattle thefts, a state minister said.

The remote region has long been plagued by tribal violence, often sparked by disputes over livestock, which can lead to a cycle of revenge attacks.

But ethnic fighting has intensified in recent years, fueled by a huge supply of weapons left over from Sudan's two-decade north-south war.

The civil war, which ended in 2005, left painful scars in the south, where some ethnic groups sided with northern forces.

The United Nations and South Sudan's government fear the violence may disrupt the fragile peace process and preparations for next February's national elections, a pillar of the 2005 peace accord.

It's very worrisome in this context ... Elections in the context of insecurity is never a good thing, said the head of the U.N. Office for the Coordination of Humanitarian Affairs in South Sudan, Lise Grande.

We're very worried right now about the intensification of the attacks and the fact ... women and children are being targeted.

Upper Nile state's information minister, Thon Mom, told Reuters 41 people were killed and 42 injured in Friday's attack, saying it was probably linked to cattle raiding. The Lou Nuer attacked the Jikany, he said.

A U.N. official, who asked not to be named, said sources on the ground had reported 49 dead and 54 injured, 24 of them severely. He said most of the dead were women and children, and that emergency medical teams had been sent to the area.

More than 700 people were killed in similar fighting between the Lou Nuer and the Murle tribe in March and April.

On Monday leaders from the Mundari and Bari ethnic groups met to try to settle differences after clashes in recent weeks close to the south's capital, Juba.

South Sudan Peace Commission Chairman Louis Lobong was also worried about the national elections.

People may not be able to campaign freely. Mundari will not be able to go to Bari areas (and vice versa), he said. It is very dangerous. People may also not accept the results.

Sudan