South Sudan's army on Saturday said it has not received any order to end fighting with forces loyal to former South Sudan vice-president Riek Machar.

"We have not received any order to cease fire," Philip Aguer, an army spokesperson, told Xinhua by phone, adding the army was continuing its operations against the rebels.

The Inter-governmental Authority for Development (IGAD) on Friday concluded a meeting in Nairobi, announcing that South Sudan has agreed on an immediate cease-fire with the rebels loyal to Riek Machar.

IGAD, in a communique released after the summit, urged Machar to declare his commitment to cease-fire and cessation of hostilities.

South Sudan, meanwhile, announced on Twitter its agreement in principle on an immediate cease-fire, but warned its forces would defend themselves if attacked.

Machar, for his part, reportedly said that a cease-fire necessitated negotiations between the two parties and a mechanism to monitor their commitment to it.