Gunmen killed at least 51 people in the latest ethnic clashes in South Sudan's troubled Jonglei state, the region's governor said Tuesday.

"The whole night (Monday) they burned the town... 51 are confirmed dead and now we have 22 (injured) evacuated to Juba," said Jonglei governor Kuol Manyang.

Armed men stormed the village of Duk Padiet in northern Jonglei late Monday, with most of those killed "women, children and the elderly," Manyang told AFP.

"We are expecting more to be injured because they ran to the villages last night," he said, blaming gunmen from the Murle ethnic group for the attack.

Remote and impoverished Jonglei has seen a dramatic escalation of bloody tit-for-tat attacks between rival ethnic groups over cattle raids and abduction of people.

Newly-independent South Sudan has declared Jonglei a national "disaster area" while the United Nations has launched a "massive emergency" operation to help some 60,000 people affected by the violence.

Last month an 8,000-strong tribal militia of Lou Nuer youths marched on Pibor, to exact revenge on the Murle people there for alleged attacks, abductions and cattle raiding.

Now officials claim the latest violence is the Murle's response.

One attacker was killed, a suspected Murle man wearing military fatigues, Manyang said.

The village "was attacked by people positively identified as the Murle armed youth," said Philip Thon Leek Deng, the local MP.

Deng said that large herds of cattle had been stolen in a series of raids in area last week, but the attack Monday targeted people.

"They did not take cattle... they are only coming for annihilation," he said.

The people of Duk Padiet are from the Dinka ethnic group, who are also traditional rivals of the Murle.