Prime Minister Hailemariam Desalegn of Ethiopia and President Uhuru Kenyatta of Kenya have arrived in Juba for a meeting with South Sudanese President Salva Kiir.
The Ugandan President Yoweri Museveni dispatched his prime minister to represent him.
The East African leaders are expected to discuss the peace process facilitated by IGAD, the Inter-Governmental Authority on Development (IGAD).
Hailemariam is chairman of IGAD and guarantor of the 9 May agreement to end the conflict in South Sudan.
IGAD-led peace talks have been adjourned for several weeks to allow for high-level consultations such as this meeting between Kiir and the East African leaders.