Khartoum, Dec 28 (IANS): South Sudan's army 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) Friday concluded a meeting in Nairobi, announcing that South Sudan has agreed to an immediate ceasefire with the rebels loyal to Machar.

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

South Sudan, meanwhile, announced on Twitter its agreement in principle on the immediate ceasefire, but warned its forces would defend themselves if attacked.

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