Armed men have attacked Pibor, a town in South Sudan.
Colonel Philip Aguer told the BBC that a hospital and other parts of the town have been set alight.
United Nations troops and the South Sudanese army were unable to prevent the attack by an estimated 6000 fighters from the Lou Nuer tribe. Pibor is home to the Murle tribe.
The United Nations deployed more combat troops to defend the town on Friday, after the entire town of Lukangol was burnt to the ground last week.
About 1000 people have been killed in Jonglei state in recent months, after a wave of cattle rustling.