JUBA, Sudan, Aug 22 (Reuters) - Thirteen people have been killed and 31 injured in cattle raids in south Sudan, where the semi-autonomous government is trying to disarm civilians after decades of civil war, an official said on Friday.

Armed men from one community in Jonglei State raided a neighbouring group on Thursday, avenging an earlier cattle theft, state governor Kuol Manyang said. The men had also attacked soldiers camped nearby.

"They went and attacked their position and killed six (soldiers) and five were wounded," Manyang said. At least seven civilians were also killed and another 26 wounded. (Reporting by Skye Wheeler, Editing by Opheera McDoom and Mariam Karouny)