At least 200 people have been wounded in a week of bitter fighting in South Sudan\’s Jonglei state, the top United Nations humanitarian official in the country said Sunday.

At least 200 people have been wounded in a week of bitter fighting in South Sudan's Jonglei state, the top United Nations humanitarian official in the country said Sunday.

“Some 200 casualties have arrived in Manyabol", a remote village in the troubled eastern state of Jonglei, where militia gunmen from rival ethnic groups have been battling, UN humanitarian coordinator for South Sudan Tony Lanzer said in a statement.

Manyabol is only one settlement in a vast region affected by the fighting, raising concerns that the number injured or killed elsewhere in the impoverished state could be far higher.

No figures were given on any possible deaths, but Lanzer called on leaders "urgently to halt the cycle of violence that is leading to senseless loss of life and suffering amongst civilians."

The UN were airlifting the most critically injured to Jonglei's state capital Bor for medical treatment, where Doctors Without Borders (MSF - Medecins Sans Frontieres) are supporting the basic hospital.

"We've seen gunshot wounds and leg fractures," MSF spokesman Martin Searle told AFP, adding that they had received 22 patients so far. "We're expecting more."

Local government officials have reported columns of hundreds -- if not thousands -- of gunmen in a tribal militia fighting their way towards the heartland of a rival community.