Juba has accused Khartoum of trying to open a new front for fighting in Upper Nile state in South Sudan but Khartoum has denied this claim.

South Sudan's military spokesman Philip Aguer said Sudanese forces attacked Kuek on Sunday near the border with White Nile state in Sudan.

He said it was the same military base attacked by the Sudanese army last November.

Aguer said South Sudan responded to the attack and managed to expel Sudanese forces.

He accused Khartoum of stoking tensions in Western Bahr el Ghazal and encouraging the Rizeigat to join the army and fight saying this would be detrimental to securiity for local residents.