JUBA, June 29 (Xinhua) -- South Sudanese President Salva Kiir has ordered implementation of the permanent ceasefire signed recently with rebel leader Riek Machar in the Sudanese capital.

President Kiir's order aired on State radio on Thursday evening calls on government forces to remain vigilant in their positions and fight only in self-defense and also allow unhindered humanitarian access.

"I Salva Kiir do hereby issue this republican order for declaration of permanent ceasefire with effect from June 30, 2018 and to continue in full operation permanently until otherwise. The SPLA forces shall remain vigilant in their positions and to fight only in an act of self-defense," he said in Juba.

President Kiir and Machar, the leader of the main rebel group the Sudan People's Liberation Movement/Army-In Opposition (SPLM/A-IO), agreed to permanent ceasefire on Wednesday in Khartoum at the recent face-to-face talks mediated by the Sudanese President Omar al-Bashir.

Both the South Sudan army (SPLA) and SPLA-IO rebels have in the past violated several ceasefire agreements particularly the Agreement on Cessation of Hostilities (ACOH) signed on December 21 2017 in Addis Ababa.

South Sudan descended into civil war in late 2013, and the conflict has created one of the fastest growing refugee crises in the world.

A 2015 peace agreement was shattered when the warring parties renewed fighting in July 2016 in the capital, forcing rebel leader Riek Machar to flee into exile.

The UN estimates that about 4 million South Sudanese have been displaced internally and externally.   

Xinhua