57 killed in new South Sudan clashes: government

New ethnic clashes in South Sudan's troubled Jonglei state have killed 57 people, the government of the world's newest nation said late Thursday.

Information Minister Barnaba Marial Benjamin said that in the latest clash "57 people got killed, and most of them are women and children. The men among them are only 11."

The minister added that a further 53 people were wounded in the attack on Wek village in Uror county on Wednesday.

Around 60 members from the Murle tribe dressed in military uniforms carried out the raid, taking over 20,000 cows from the rival Nuer tribe area as part of an ongoing cattle vendetta.

"The Murle attacked from 1700 hours (1400 GMT) until midnight. That’s why so many families got killed in their homes," Benjamin added.

South Sudan has declared Jonglei a national "disaster area" while the United Nations has said it will launch a "massive" emergency operation to help some 60,000 people affected by the violence.

In a dramatic escalation of bitter tit-for-tat attacks, a militia army of several thousand Lou Nuer youths recently marched on Pibor, another settlement in the remote area, to exact revenge on the Murle who they blame for abductions and cattle raiding.

The UN says that last year, violence between the two tribes left around 1,100 people dead and tens of thousands displaced, and that the conflict shows no signs of abating.

"This is a revenge attack -- definitely they are coming to attack the Lou Nuer," Benjamin said of the most recent attack.

Medical charity Doctors without Borders (Medecins Sans Frontieres - MSF) said it had airlifted 12 people to its hospital in Nasir, in neighbouring Upper Nile state for urgent surgical treatment.

"Five adult women and one adult man had gunshot wounds and the remaining six patients were children under five, with beating or gunshot wounds," MSF said in a statement.

The statement said the group's head of mission Jose Hulsenbeck "expressed shock at the number of women and children injured in this latest round of violence."

Benjamin said 100 troops were already on their way to the remote area in northern Jonglei from a base in Wat, 50 kilometres (35 miles) away, and more would soon follow.

After an attack on a Nuer area on Sunday that reportedly killed 24 people, Jonglei governor Kuol Manyang warned that a Murle captain had "deserted with 30 people" to take revenge for his people.

Benjamin could not say immediately whether the men accused of the latest attack had defected from the army.

In all of the latest attacks in Jonglei crops have been razed, cattle stolen and homes torched.

The state was one of the areas hardest hit in Sudan's two-decade-long north-south civil war, which ended in a 2005 peace deal that paved the way for South Sudan's full independence.